National Waterworks and Sewerage Authority vs. NWSA Consolidated Unions

A government-owned and controlled corporation performing proprietary functions—such as providing water supply and sewerage services—is covered by the Eight-Hour Labor Law (Commonwealth Act No. 444), notwithstanding its public character; but where it qualifies as a public utility, it is exempt from the statutory requirement of additional 25% compensation for Sunday and holiday work, unless it has contractually assumed such obligation through a collective bargaining agreement, in which case it must pay not by compulsion of law but by contractual obligation.

NAWASA is a government-owned and controlled corporation created under Republic Act No. 1383, tasked with consolidating and centralizing all waterworks, sewerage, and drainage systems in the Philippines under one control and direction. The respondent NWSA Consolidated Unions are various labor organizations composed of NAWASA's laborers and employees. Intervenors Jesus Centeno, Cesar Cabrera, Feliciano Duiguan, Cecilio Remotigue, and other employees receiving ₱4,200 per annum or more are individual NAWASA employees who intervened in the proceedings. The dispute was certified by the President of the Philippines to the Court of Industrial Relations, encompassing multiple labor issues arising under the Eight-Hour Labor Law (C.A. No. 444), the 40-Hour Week Law (R.A. No. 1880), and a collective bargaining agreement dated December 28, 1956.

The National Waterworks and Sewerage Authority (NAWASA) is a government-owned and controlled corporation created under Republic Act No. 1383, charged with consolidating and centralizing all waterworks, sewerage, and drainage systems in the Philippines. The respondent NWSA Consolidated Unions are various labor organizations composed of NAWASA's laborers and employees. The intervenors—Jesus Centeno, Cesar Cabrera, Feliciano Duiguan, Cecilio Remotigue, and other employees receiving ₱4,200 per annum or more—are individual NAWASA employees who sought to participate in the proceedings to assert claims for night work and overtime compensation.

Acting on a certification by the President of the Philippines, the Court of Industrial Relations conducted a hearing on December 5, 1957, on the controversy existing between NAWASA and the respondent unions. The unions had embodied their grievances in a Manifesto, raising multiple issues: implementation of the 40-Hour Week Law (R.A. No. 1880); alleged violations of the collective bargaining agreement dated December 28, 1956 concerning "distress pay"; minimum wage of ₱5.25; promotional appointments and filling of vacancies; additional compensation for night work; wage increases; and strike duration pay. The unions also raised whether the 25% additional compensation for Sunday work should be included in computing the daily wage, and whether the salary of a monthly-salaried employee should be divided by 30 days to determine the daily wage. On December 13, 1957, the parties submitted a joint stipulation of facts on the issues concerning the 40-Hour Week Law, distress pay, minimum wage, filling of vacancies, night compensation, and salary adjustments, reserving the right to present evidence on matters not covered by the stipulation.

On December 4, 1957, the intervenors filed a petition for intervention on the issue of additional compensation for night work. They later amended their petition to include a new demand for overtime pay. On February 5, 1958, NAWASA filed a motion to dismiss the overtime claim, arguing that the Court of Industrial Relations lacked jurisdiction because the intervenors, as mere intervenors, could not raise new issues not litigated in the principal case. The CIR overruled the opposition and allowed the issue to be litigated. After NAWASA's motion for reconsideration was denied, it filed its answer to the petition for intervention.

On January 16, 1961, the Court of Industrial Relations rendered its decision. It held that NAWASA is an agency not performing governmental functions and is liable for additional compensation for Sunday and holiday work under C.A. No. 444; that the intervenors are not managerial employees under R.A. No. 2377; that the computation method used by NAWASA for overtime compensation was contrary to C.A. No. 444; that undertime should not be set off against overtime; that the 25% Sunday differential should be included in computing the daily wage; that dividing the monthly basic pay by 30 was erroneous; that the minimum wage awarded in a prior case applied to employees hired after the award; that the staggering of work days should be limited to those specified in the President's authorization; and that distress pay should be paid to those working in and outside the sewerage chambers. NAWASA's motion for reconsideration was denied, prompting the present petition for review raising only questions of law.

The CIR found, as factual matters relevant to the Supreme Court's analysis, that the intervenors' primary duties do not bear direct relation to the management of NAWASA, that they do not participate in policy formulation or hiring and firing, that they are required to observe working hours and record their time, and that they are not free to come and go at their own discretion. The CIR also found that the sewerage division's three main activities—operation of sewerage pumping stations, cleaning and maintenance of sewer mains, and installation and repair of house sewer connections—all involve exposure to sewage, foul odor, and health hazards causing unusual distress to workers both inside and outside the sewerage chambers. Finally, the CIR found that personnel in construction, sewerage, maintenance, machineries, and shops work less than 365 days a year and their services are not continuous so as to require staggering of work days.

• Governmental Functions: Petitioner argued that NAWASA performs governmental functions because under Republic Act No. 1383 it is a public corporation existing as an agency independent of the Department of Public Works, the Public Service Commission has no control or jurisdiction over it in fixing rates, and it can incur indebtedness or issue tax-exempt bonds—an attribute of sovereignty. Petitioner likewise invoked the opinion of the Secretary of Justice holding that NAWASA is essentially a service agency of the government performing governmental functions.
• Public Utility Exemption: Petitioner contended that NAWASA is a public utility and therefore exempt from paying additional compensation for work on Sundays and legal holidays under Section 4 of Commonwealth Act No. 444.
• Managerial Employee Status: Petitioner claimed that the intervenors are "managerial employees" within the meaning of Republic Act No. 2377 and therefore not entitled to the benefits of Commonwealth Act No. 444.
• Jurisdiction over Overtime Claim: Petitioner maintained that the Court of Industrial Relations lacked jurisdiction to adjudicate the overtime pay claim because it was not among the demands in the principal case and was merely raised by intervenors, citing Section 1, Rule 13 of the Rules of Court.
• Undertime Offset: Petitioner argued that undertime incurred during a regular work day should be set off against overtime work in determining whether an employee rendered service in excess of eight hours.
• Daily Wage Computation: Petitioner contended that the daily wage should be computed exclusively on the basic wage, without including the 25% Sunday differential, because including it would increase the basic pay beyond what Republic Act No. 1880 contemplates.
• Monthly Salary Computation: Petitioner argued that the daily rate of a monthly-salaried employee should be computed by dividing the monthly basic pay by 30, in accordance with Section 254 of the Revised Administrative Code.
• Prospective Night Compensation: Petitioner theorized that since no statute requires payment of additional compensation for night work—such payment emanating only from voluntary employer action or an award of the industrial court under its compulsory arbitration power—the grant should be prospective, not retroactive.
• Distress Pay Scope: Petitioner contended that distress pay should be given only to those who actually work inside the sewerage chambers, not to those working outside.
• Staggering of Work Days: Petitioner appealed from the CIR's ruling limiting the staggering of work days, contending that it should extend to personnel in construction, sewerage, maintenance, machineries, and shops.

• Undertime Offset: Respondent unions argued that undertime should not be set off against overtime work in determining whether an employee rendered service in excess of eight hours.
• Distress Pay Scope: The union maintained that distress pay should be given to all those whose work has to do with the sewerage chambers, whether inside or outside.

• Nature of NAWASA's Functions: Whether NAWASA performs governmental functions and is therefore essentially a service agency of the government exempt from the Eight-Hour Labor Law.
• Public Utility Exemption: Whether NAWASA is a public utility and therefore exempt from paying additional compensation for work on Sundays and legal holidays under Commonwealth Act No. 444.
• Managerial Employee Status: Whether the intervenors are "managerial employees" within the meaning of Republic Act No. 2377 and therefore not entitled to the benefits of Commonwealth Act No. 444, as amended.
• CIR Jurisdiction over Overtime Claim: Whether the Court of Industrial Relations has jurisdiction to adjudicate the overtime pay claim raised by intervenors, considering it was not among the demands in the principal case.
• Status of GAO and BPW Employees: Whether employees attached to the General Auditing Office and the Bureau of Public Works come within the purview of Commonwealth Act No. 444.
• Undertime Offset: Whether undertime for a given day should be set off against overtime work in determining whether an employee rendered service in excess of eight hours.
• Sunday Differential in Wage Computation: Whether the additional 25% compensation for Sunday work should be included in computing the daily wage.
• Daily Wage of Monthly-Salaried Employees: What is the correct method to determine the equivalent daily wage of a monthly-salaried employee, especially in a firm which is a public utility.
• Retroactivity of Night Compensation: Whether night compensation awarded by the CIR, not being required by statute but emanating from an award of the industrial court, can be made retroactive to cover a period prior to the promulgation of the award.
• Applicability of Prior Minimum Wage Award: Whether the minimum wage fixed in CIR Case No. 359-V applies to those employed long after the promulgation thereof, including temporary, emergency, and casual workers hired for a definite period and a specific project.
• Distress Pay Interpretation: How the collective bargaining agreement of December 28, 1956 and Resolution No. 29, series of 1957 of the Grievance Committee should be interpreted insofar as the stipulations on "distress pay" are concerned.
• Scope of Work-Day Staggering: Whether, under the President's authorization dated August 12, 1957, employees whose services are indispensably continuous throughout the year may be staggered in the same manner as pump, valve, filter, and chlorine operators, guards, watchmen, medical services, and those attached to recreational facilities.

• Nature of NAWASA's Functions: No. NAWASA, though a public corporation, does not perform governmental functions; it performs proprietary functions and comes within the coverage of Commonwealth Act No. 444.
• Public Utility Exemption: Yes, NAWASA is a public utility exempt from mandatory 25% Sunday/holiday premium under Section 4 of C.A. No. 444. However, it must pay such compensation by virtue of its contractual obligation under the collective bargaining agreement, not by compulsion of law.
• Managerial Employee Status: No. The intervenors are not managerial employees under Republic Act No. 2377 because their primary duties do not involve management, policy formulation, or hiring and firing, and they are required to observe fixed working hours.
• CIR Jurisdiction over Overtime Claim: Yes. The CIR has jurisdiction because an employer-employee relationship existed between the intervenors and NAWASA, and technicalities of procedure should be avoided in labor disputes to prevent multiplicity of action.
• Status of GAO and BPW Employees: No. GAO and Bureau of Public Works employees assigned to NAWASA are employees of the national government, not of NAWASA, and are not covered by the Eight-Hour Labor Law.
• Undertime Offset: No. The method of offsetting overtime with undertime while simultaneously charging undertime to accrued leave is unfair, as it makes the employee pay twice for undertime. The proper method is to deduct undertime from accrued leave but pay the overtime to which the employee is entitled.
• Sunday Differential in Wage Computation: Yes. The 25% Sunday differential is part of the regular wage and was correctly included in computing the weekly wages of employees who worked seven days a week and regularly received the differential for three months prior to the implementation of R.A. No. 1880.
• Daily Wage of Monthly-Salaried Employees: For non-government employees, the correct computation is the monthly salary divided by the actual number of working hours in the month, or the regular monthly compensation divided by the number of working days in the month. For government employees (GAO and BPW), Section 254 of the Revised Administrative Code applies—dividing the monthly pay by the number of days in the particular month.
• Retroactivity of Night Compensation: Yes. The CIR did not err in ordering retroactive payment of night compensation from the time the services were rendered, as workers often delay asserting claims for fear of reprisal.
• Applicability of Prior Minimum Wage Award: Yes. The minimum wage rates fixed in CIR Case No. 359-V apply not only to those already in service at the time of the award but also to those employed subsequent thereto, including temporary, emergency, and casual workers.
• Distress Pay Interpretation: Distress pay should be paid to all laborers, whether or not assigned to the sewerage division, who actually work in and outside the sewerage chambers, effective October 1, 1956. "Sewerage chambers" includes the surroundings where the work is actually done.
• Scope of Work-Day Staggering: The CIR's finding that personnel in construction, sewerage, maintenance, machineries, and shops work less than 365 days a year and do not require staggering was not disturbed, as it is consistent with the original request that staggering apply only to operations requiring continuous 24-hour attendance.

• Nature of NAWASA's Functions: While Republic Act No. 1383 created NAWASA as a public corporation, this does not mean it was created for the government of a portion of the State. There are two kinds of public corporations: municipal and non-municipal. A municipal corporation is a body politic constituted by inhabitants of a city or town for local government. NAWASA was created to consolidate and centralize waterworks and sewerage systems—not to regulate local affairs. It has personality and power separate and distinct from the government, with its own assets, liabilities, and authority to charge rates. The business of providing water supply and sewerage service may be likened to an industry engaged in by coal companies, gas companies, power plants, and ice plants—these are mere ministrant functions of government, optional in nature. As such, NAWASA performs proprietary functions and comes within the coverage of Commonwealth Act No. 444.

• Public Utility Exemption: NAWASA's primary function of constructing, maintaining, and operating water reservoirs and waterworks makes it a public utility. Section 4 of C.A. No. 444 exempts public utilities supplying water from the requirement of paying 25% additional compensation for Sunday and holiday work. However, it was stipulated that prior to R.A. No. 1880, the Metropolitan Water District had been paying 25% additional compensation for Sunday and holiday work by virtue of Resolution No. 47, series of 1948, a practice continued by NAWASA. The collective bargaining agreement provided that all existing benefits enjoyed prior to its effectivity shall remain in force. While C.A. No. 444 does not require a public utility to pay such additional compensation, there is no prohibition against voluntary payment. NAWASA committed itself contractually and must pay not because of legal compulsion but because of contractual obligation.

• Managerial Employee Status: Republic Act No. 2377 exempts managerial employees from the Eight-Hour Labor Law. A managerial employee is one whose primary duty consists of management of the establishment or a recognized department thereof, or an officer or member of the managerial staff. A key distinguishing characteristic is that a managerial employee is not subject to rigid observance of regular office hours; the true worth of his service depends on results, not time spent. Drawing from the Fair Labor Standards Act, the exemption applies where the employee's primary duty consists of management, customarily directs the work of others, has authority to hire or discharge, and exercises discretionary powers. The intervenors hold positions such as Secretary of the Board, private secretary of the general manager, public relations officer, and chiefs of divisions or sections. The CIR found that their primary duties do not bear direct relation to management, they do not participate in policy formulation or hiring and firing, and they are given ready policies to execute with little freedom of action. They are required to observe working hours and record their time. They therefore do not qualify as managerial employees.

• CIR Jurisdiction over Overtime Claim: The intervenors were in the employ of NAWASA when they intervened, and their claim refers to the Eight-Hour Labor Law. The Court has consistently held that disputes calling for the application of the Eight-Hour Labor Law are within the jurisdiction of the Court of Industrial Relations when they arise while the employer-employee relationship still exists. The fact that the overtime payment question was not included in the original certification by the President is of no moment, as it falls within the sound discretion of the CIR. Moreover, technicalities of procedure should be avoided in labor disputes to prevent multiplicity of action.

• Status of GAO and BPW Employees: The status of GAO employees assigned to government-controlled corporations was settled in National Marketing Corporation vs. Court of Industrial Relations, where the Court held that auditing force members cannot be regarded as employees of the corporation in matters relating to compensation. They are appointed and supervised by the Auditor General, have independent tenure, and work subject to his orders. Their inclusion in the corporation's budget is merely a designation of the fund source, not a sign of employment. The same reasoning applies to Bureau of Public Works employees assigned to NAWASA. They are government employees, not NAWASA employees, and are not covered by C.A. No. 444 but by other pertinent laws.

• Undertime Offset: The method used by NAWASA of offsetting overtime with undertime while simultaneously charging the undertime to accrued leave is unfair because it makes the employee pay twice for undertime—his leave is reduced while he is made to compensate with work beyond regular hours. The proper method is to deduct undertime from accrued leave but pay the employee the overtime to which he is entitled. This also avoids irregular work schedules that would result if overtime were set off against undertime, which would place working hours dependent on the employee.

• Sunday Differential in Wage Computation: Republic Act No. 1880 does not intend to raise wages but to limit working days to five days or 40 hours without permitting reduction in the weekly or daily wage previously received. The question is whether "regular wage" includes differential payments for Sunday work. Jurisprudence holds that for purposes of computing compensation, the regular wage includes all payments agreed to be received during the work week, including differential payments for working at undesirable times such as Sundays and holidays. The higher rate for Sunday work is just as much a regular rate as the lower rate for daytime work; it is merely an inducement to accept employment at less desirable times. The CIR therefore correctly included the Sunday differential in computing weekly wages of employees who worked seven days a week and regularly received the 25% differential for three months prior to R.A. No. 1880's implementation.

• Daily Wage of Monthly-Salaried Employees: The CIR held that the daily rate of a monthly employee should be computed by dividing the monthly salary by the actual number of working hours in the month, or the regular monthly compensation divided by the number of working days in the month, pursuant to Section 8(g) of R.A. No. 1161, as amended by R.A. No. 1792. This was found correct for non-government employees. However, for GAO and Bureau of Public Works employees assigned to NAWASA—who are government employees—Section 254 of the Revised Administrative Code applies, which provides that in making payment for part of a month, the amount for each day shall be determined by dividing the monthly pay into as many parts as there are days in the particular month. With this modification, the CIR's finding was upheld.

• Retroactivity of Night Compensation: It is common for a worker who has rendered night-time service to take a long time before mustering enough courage to confront his employer with a demand for payment, for fear of reprisal. Months or years may pass before the claim is presented. It is neither fair nor just to deprive the worker of what is due simply because of silence born of fear of losing his livelihood. The power of the CIR to order payment of compensation for overtime service prior to the filing of the claim was recognized in Luzon Stevedoring Co., Inc. vs. Luzon Marine Department Union. The same reasoning supports retroactivity of night compensation.

• Applicability of Prior Minimum Wage Award: The minimum wage rates fixed in CIR Case No. 359-V continued to be valid and effective despite the notice of termination filed by the employer, because the notice was given without hearing and the employer continued paying the rates afterward. There is nothing in the award preventing its extension to employees hired after its approval. The industrial court may reopen any question during the effectiveness of an award under Section 17 of C.A. No. 103. Extending the award to similarly situated new employees prevents discrimination.

• Distress Pay Interpretation: The collective bargaining agreement provides 25% extra compensation for employees of the Sewerage Division who actually work in sewerage chambers causing "unusual distress." Resolution No. 9 of the Grievance Committee expanded "sewerage chambers" to include pits, trenches, and other excavations necessary to tap sewer lines, and provided that any employee required to work actually in the sewerage chambers shall also be paid. The November 25, 1957 conference agreement stipulated payment to those who "actually work in and outside sewerage chambers." Interpreting these stipulations as a whole under Article 1374 of the Civil Code, those entitled to distress pay are all employees and laborers who work in and outside the sewerage chambers, whether or not they belong to the sewerage division. "Sewerage chambers" should be understood as the surroundings where the work is actually done. The CIR's findings on the three main activities of the sewerage division—pumping station operation, sewer main cleaning, and house connection installation—confirm that workers in all three activities suffer unusual distress from exposure to sewage, foul odor, and health hazards.

• Scope of Work-Day Staggering: The CIR found that workers in construction, sewerage, maintenance, machineries, and shops work less than 365 days a year and their services are not continuous enough to require staggering. This finding is consistent with NAWASA's own request, which sought staggering only for operations requiring continuous 24-hour attendance without interruption. There is no reason to disturb the CIR's finding, as extending staggering to workers whose services are not continuous would contradict the very basis of the authorization.

• Governmental vs. Proprietary Functions of Government-Owned Corporations — A public corporation may be municipal (created for local government) or non-municipal (created as an agency of the State for limited purposes other than community government). A government-owned and controlled corporation that provides water supply and sewerage services performs proprietary, not governmental, functions, because such services are ministrant functions—optional in nature and aimed at advancing the general interest of society. As such, the corporation is covered by the Eight-Hour Labor Law. The test is whether the corporation was created to regulate local affairs (governmental) or to perform a business or service function (proprietary).

• Public Utility Exemption and Contractual Obligation — Under Section 4 of Commonwealth Act No. 444, public utilities supplying gas, electricity, power, water, or providing transportation or communication are exempt from the statutory requirement of paying 25% additional compensation for Sunday and holiday work. However, there is no prohibition against voluntary payment. Where a public utility has contractually assumed the obligation to pay such compensation—through a board resolution, practice, or collective bargaining agreement—it must pay not by compulsion of law but by force of contractual obligation.

• Definition of Managerial Employee — Under Republic Act No. 2377, a managerial employee is one whose primary duty consists of the management of the establishment or a customarily recognized department thereof, or an officer or member of the managerial staff. A key characteristic is that the employee is not subject to rigid observance of regular office hours; the worth of his service depends on results, not time spent. The exemption from the Eight-Hour Labor Law is based on the philosophy that such workers are not employed at hourly wages, their compensation reflects special training and discretion, and it is not feasible to provide fixed hourly rates or maximum hours. Employees who observe fixed working hours, record their time, do not participate in policy formulation, and have little freedom of action are not managerial employees.

• Regular Wage Includes Differential Payments — For purposes of computing wages under the 40-Hour Week Law, the regular wage includes all payments which the parties have agreed shall be received during the work week, including differential payments for working at undesirable times such as Sundays and holidays. The higher rate for Sunday and holiday work is just as much a regular rate as the lower rate for daytime work; it is merely an inducement to accept employment at less desirable times.

• Retroactivity of Labor Awards — The Court of Industrial Relations may order payment of compensation for services rendered prior to the filing of the claim. Workers often delay asserting claims for fear of reprisal, and it is neither fair nor just to deprive them of what is due simply because of silence born of fear of losing their livelihood.

• Status of GAO Employees Assigned to GOCCs — Employees of the General Auditing Office assigned to work in government-owned and controlled corporations are not employees of the corporation in matters relating to compensation. They are appointed and supervised by the Auditor General, have independent tenure, and work subject to his orders. Their inclusion in the corporation's budget is merely a designation of the fund source. This independence is necessary to assure maximum impartiality in auditing functions.

• "The NAWASA committed itself to pay this additional compensation. It must pay not because of compulsion of law but because of contractual obligation." — This passage articulates the principle that while a public utility is statutorily exempt from mandatory Sunday/holiday premium pay, a voluntary contractual commitment to pay such compensation is binding and enforceable.

• "The business of providing water supply and sewerage service, as this Court held, 'may for all practical purposes be likened to an industry engaged in by coal companies, gas companies, power plants, ice plants, and the like'" — This passage defines the proprietary character of NAWASA's operations by analogizing water and sewerage services to private industries, establishing the governmental/proprietary function distinction for GOCCs.

• "The philosophy behind the exemption of managerial employees from the 8-Hour Labor Law is that such workers are not usually employed for every hour of work but their compensation is determined considering their special training, experience or knowledge which requires the exercise of discretion and independent judgment, or perform work related to management policies or general business operations along specialized or technical lines." — This passage provides the doctrinal basis for the managerial employee exemption, explaining why such employees are excluded from the Eight-Hour Labor Law's coverage.

• "It is of common occurrence that a working man who has already rendered night time service takes him a long time before he can muster enough courage to confront his employer with the demand for payment for it for fear of possible reprisal." — This passage states the rationale for allowing retroactive awards of night compensation, recognizing the practical realities that delay workers from asserting their claims.

• Bacani vs. National Coconut Corporation, 53 O.G. 2798 — Followed. The Court relied on this case to distinguish governmental entities (which exercise functions as an attribute of sovereignty, including municipal corporations) from government entities given corporate personality separate and distinct from the government and governed by the Corporation Law. This distinction supported the conclusion that NAWASA performs proprietary functions.

• Metropolitan Water District vs. Court of Industrial Relations, L-4488, August 27, 1952 — Followed. The Court cited this case for the proposition that the business of providing water supply and sewerage service may be likened to an industry engaged in by coal companies, gas companies, power plants, and ice plants—i.e., ministrant or proprietary functions.

• Mendoza vs. De Leon, 33 Phil. 508 — Followed. The Court cited this case for the distinction between governmental functions (fire regulation, public peace, prisons, schools) and corporate or business functions (waterworks, slaughterhouses, markets, wharves), supporting the classification of waterworks as proprietary.

• National Marketing Corporation vs. Court of Industrial Relations, L-17804, January 31, 1963 — Followed. The Court applied this case's ruling on the status of GAO employees assigned to government-controlled corporations—holding they are not employees of the corporation but of the national government—to the GAO employees assigned to NAWASA.

• Luzon Stevedoring Co., Inc. vs. Luzon Marine Department Union, L-9265, April 29, 1957 — Followed. The Court cited this case as recognizing the power of the CIR to order payment of compensation for overtime service prior to the filing of the claim, supporting the retroactivity of night compensation awards.

• Republic Act No. 1383 — The NAWASA charter. The Court examined its provisions, particularly Section 2(e), (f), and (g), to determine the nature of NAWASA's powers and functions, concluding that they are proprietary rather than governmental.
• Commonwealth Act No. 444 (Eight-Hour Labor Law), Section 4 — Provides that the prohibition on Sunday and holiday work without 25% additional compensation shall not apply to public utilities supplying gas, electricity, power, water, or providing transportation or communication. Applied to exempt NAWASA from mandatory Sunday/holiday premium, while noting that voluntary contractual payment remains binding.
• Republic Act No. 1880 (40-Hour Week Law) — Limits working days to five days or 40 hours per week without permitting reduction in the weekly or daily wage previously received. Applied to determine that Sunday differential pay must be included in computing weekly wages to prevent diminution.
• Republic Act No. 2377, Section 2 — Defines "managerial employee" and exempts such employees from the coverage of the Eight-Hour Labor Law. Applied to determine that the intervenors do not qualify as managerial employees because their duties do not involve management, policy formulation, or discretion.
• Section 254, Revised Administrative Code — Provides that in making payment for part of a month, the amount for each day shall be determined by dividing the monthly pay into as many parts as there are days in the particular month. Applied to government employees (GAO and BPW) assigned to NAWASA for computing their daily wage.
• Section 8(g), Republic Act No. 1161, as amended by Republic Act No. 1792 — Provides that the daily rate of compensation is the total regular compensation for the customary number of hours worked each day. Applied as the basis for the CIR's method of computing the daily rate of monthly-salaried non-government employees.
• Article 1374, Civil Code — Provides that stipulations in a contract shall be interpreted as a whole. Applied to interpret the collective bargaining agreement, Resolution No. 9, and the November 25, 1957 conference agreement on distress pay.
• Section 17, Commonwealth Act No. 103 — Authorizes the industrial court to reopen any question involved in an award during its effectiveness. Applied to uphold the extension of the minimum wage award in CIR Case No. 359-V to subsequently hired employees.
• Executive Order No. 251 — Prescribes office hours for government and government-owned or controlled corporations. NAWASA sought exemption from this order to stagger working hours, which was granted by the President.

Bengzon, C.J., Concepcion, Reyes, J.B.L., Paredes, Regala, and Makalintal, JJ., concurred.