Last Updated 08/07/2026
San Juan Stormwater Laws & Regulations
In 1972, Congress amended the Federal Water Pollution Control Act, commonly referred as the Clean water Act (CWA) to prohibit the discharge of any pollutant to waters of the United States from point sources unless the discharge is authorized by a National Pollutant Discharge Elimination System (NPDES) permit. Initial efforts under the NPDES program focused on reducing pollutants in discharges of industrial process wastewater and municipal sewage. As pollution control measures have been implemented, it has become evident that diffuse sources or non-point sources (ex. stormwater runoff from developed areas) are also contributors of water quality degradation. In 1990, the US Environmental Protection Agency (USEPA) promulgated rules establishing Phase I of the NPDES storm water program. The Phase I program for MS4 requires operators of “medium” and “large” MS4, that is, those that generally serve populations of 100,000 or greater, to implement a storm water management program as a means to control polluted discharges from these MS4. USEPA published the Storm Water Phase II Rule on December 9, 1999. As outlined in these regulations the Municipality of San Juan is required to submit an application for permit coverage.
The urbanized and rural areas of Municipality of San Juan, as well as the City itself, are required to apply for NPDES municipal storm water discharge permits. In order to assure that the quality of storm water discharges from our municipal storm sewer system is managed to the maximum extent practicable, the Municipality of San Juan has developed and is in the process of implementing a Storm Water Management Program (SWMP) that includes best management practices, public education, and storm water monitoring. The Municipality of San Juan’s SWMP addresses core requirements as six minimum control measures, and includes guidance for construction site (#4) and post-construction stormwater management in development and redevelopment.
The U.S. Environmental Protection Agency has not delegated the NPDES permitting program to the Puerto Rico Environmental Quality Board (PREQB). Thus, USEPA Region 2 has issued a general NPDES permit for Small Municipal Separate Storm for Puerto Rico as of November 6, 2006. See the
1.2 SAN JUAN’S MUNICIPAL STORM WATER SEWER SYSTEM
The Municipality of San Juan has a territorial extension of 123.8 square kilometers (47.8 sq mi), of which 75.4 km (29.11 mi) are water bodies. According to the 2000 Census, its population is 434,374 inhabitants with a population density of 3,507.26 inhabitant per sq mi.
San Juan is located in the Northeastern of Coastal Plain region. The city lies north of the municipalities of Aguas Buenas and Caguas, east of the municipalities of Guaynabo and Bayamon and west of the municipalities of Carolina and Trujillo Alto. The Municipality is comprised of 18 wards, 16 of which fall within the former municipality of Rio Piedras and 8 of which are further subdivided into sub-barrios. These are:
| 1. San Juan Antiguo | 7. Pueblo | 13. Monacillo Urbano |
| 2. Santurce | 8. Oriente | 14. Monacillo |
| 3. Hato Rey Norte | 9. Saban a Llana Norte | 15. Cupey |
| 4. Hato Rey Central | 10. Saban a Llana Sur | 16. Caimito |
| 5. Hato Rey Sur | 11. EI Cinco | 17. Tortugo |
| 6. Universidad | 12. Gobernador Pinero | 18. Quebrada Arenas |
1.9 DESCRIPTION OF THE MUNICIPAL STORM WATER SEWER SYSTEM
The Municipality of San Juan Storm Water Sewer System (MS4) in the urban areas in general consist of a series of catch basins, typically located within the right-of-way of municipal and state roads, interconnected by underground concrete or PVC pipes which normally discharge to the Atlantic Ocean. In the rural areas the Municipal MS4 system typically consists of a series of interconnected open channel culverts, which run parallel to municipal and state roads, and usually discharge to a surface water body. It is important to note that the municipal separate storm water sewer system is interconnected with the storm water sewer system operated and maintained by the Puerto Rico Department of Transportation and Public Works and that of the Highway and Transportation Authority. Also, interconnected to the Municipal MS4 system are the discharges from NPDES (stormwater) permitted facilities and PRASA Pre-treatment permitted industrial and commercial facilities.
The Municipal Public Works, Engineering and Construction Department (PWEC) is responsible for the operation and maintenance of the stormwater sewer system and associated facilities within the Municipality of San Juan. The principal responsibility of the PWEC is to perform a preventive maintenance and upgrade program. The PWEC offers services such as open channel cleaning and catch basin clean up. Open trash dumping sites elimination, street sweeping, road side vegetation maintenance, septic tank maintenance and cleaning and other related services are also rendered by the Environmental Protection Department (EPD). The Municipality also manages the Animal Protection Control Division that is responsible for eliminating dead and stray animals from the streets, which reduces pet waste and pollutants is the storm water runoff.
As the Municipality of San Juan implements the proposed Storm Water Management Plan a more accurate description (capacity, operation, etc.) of the Municipal MS4 system can be provided.
ESTIMATED SQUARE MILEAGE SERVED BY THE MS4 SYSTEM
The estimated square mileage served by the MS4 System is 47.7 m2. However, it must be noted that a more accurate estimate can be provided as the Municipality implements the proposed Storm Water Management Plan.
Excerpt – STORM WATER MANAGEMENT PLAN
The Municipality of San Juan has many regulatory and public responsibilities. One of these is the development of a Storm Water Management Plan (SWMP). The SWMP will be developed to meet the regulatory requirements of the National Pollutant Discharge Elimination System (NPDES) Phase II Rule and to assist the Municipality in maintaining and improving the Municipality drainage facilities which include pipelines, structures, basins, ditches, swales, ponds, underdrains and drainage wells, to ensure that they perform to design capacity and that all receiving bodies meet state and federal standards for water quality. It will also be an important tool for use in the day-to-day operations and as a public reference document. Along with regulatory issues, this plan will addresses protection of property from flooding and erosion, identifies health and safety issues related to water resources, and will make recommendations for the preservation of environmental and aesthetic benefits to the community.
Through the use of field observations, results of past and future studies, hydrologic/hydraulic computer modeling, and input from Municipality staff and a proposed Citizens Advisory Committee, the SWMP will identify existing problems and potential future problems within the Municipality. A combination of regulatory requirements, public education, increased maintenance activities, and capital improvements will be recommended to solve identified problems. The major plan elements include the following:
- Development of a proposed storm water ordinance that, among other things, establishes minimum requirements for new development and redevelopment, prohibits illicit discharges into surface waters, and requires maintenance of privately owned storm water facilities.
- Development of public education opportunities to inform the community of water quality issues, and, specifically, the new ordinance and its requirements.
- Develop a Storm Water Assistance Program, to assist businesses and persons in their efforts to comply with NPDES storm water regulations and will educate citizens about storm water runoff and associated concerns.
- Hydrologic and hydraulic computer modeling analysis of the major drainage basins in the Municipality to simulate existing flows, project future flows, and evaluate system requirements.
- Analysis of localized flooding and water quality problems and solutions, and development of a prioritized list of recommended drainage system improvements.
- Development of a Capital Improvements Program.
- Development of a Maintenance and Operations Program
- Development of a Public Education.
- Development of a Compliance Management Program to among other things, monitor illicit discharges into surface waters, storm water discharges associated with industrial activity and construction sites.
- Description of the overall program costs.
- Analysis of funding options and the creation of a storm water utility.
The proposed SWMP will focus initially on a system inventory and analysis of drainage and water quality issues followed by a 5 year capital improvement program, a facilities maintenance program, and a comprehensive storm and surface water code and policy.
As envisioned, the SWMP will address the drainage network base map, hydrologic and hydraulic analysis and modeling, if required, for the principal surface water bodies (creeks and rivers), environmental and water quality issues, capital improvement program, storm water facilities maintenance program and a comprehensive Storm Water Management Code and Policy.
1 .11. Task 6: Development of a Watershed Management
Task 6 provides the basis for the integration of previous and current activities for Tasks 1 through 5 and the evaluation of how those activities affect the hydrology, ecology, and economy of the Municipality. The valuable information obtained from Tasks 1 through 5 will be used to create a framework for an overall watershed strategy for the Municipality by first developing a watershed management conceptual model. The framework will help to determine what information is missing and what other factors need to be considered in order to develop the conceptual model. A model that incorporates changing demographics, land uses, water supply and demands, environmental health and ecologically sensitive areas, and a host of other information will be an essential tool for shaping a water management strategy. The emphasis is to create a strategy, rather than a plan, with which to approach watershed issues. The distinction is important if the goal of making tangible progress in solving present and future basin issues is to be achieved.
1.12.5 Minimum Control Measure 5: Post-Construction Storm Water Management in Development and Redevelopment
Target Audience -Contractors, construction site operators, inspectors, and enforcement personnel.
Goal -Developing, implementing, and enforcing a program that will reduce or eliminate the impacts of storm water runoff from new development and redevelopment projects that disturb greater than or equal to one acre, including projects that are less than one acre and are part of a larger development plan, that discharge into the storm sewer system during the permit term throughout the community.
Best Management Practices
A. Best Management Practices I (Structural) –Require new developments the incorporation of dry/wet extended detention ponds or basins with outlets that have been designed to detain the storm water runoff to allow pollutants to settle.
Measurable Goal(s) -The number of new dry/wet ponds installed.
- Porous Pavement Program -Develop a porous pavement program such that this porous surface replaces traditional pavement, allowing parking lot storm water to infiltrate directly and receive water quality treatment.
Measurable Goal(s) -The amount of new porous pavement added or replaced and the number of new development sites that use porous pavement.
- Vegetative Practices (Stormwater Wetland Program) – Develop a structural storm water wetlands program that incorporates wetland plants into the design.
Measurable Goal(s) -The number of storm water wetlands created and acreage of impervious surface that drains to storm water wetlands.
- Vegetative Practices (Grassed Swale Program) –The Municipality shall develop a series of vegetated, open channel BMPs designed to treat and attenuate storm water runoff for a specified water quality volume.
Measurable Goal(s) -The number of new grassed swales installed and acres drained by grassed swales.
- Runoff Pretreatment Practices –Develop a catch basin insert or an in-line storage program that shall typically include a grate or curb inlet and a sump to capture sediment, debris, and associated pollutants. Catch basin efficiency shall be improved using inserts that shall be designed to remove oil and grease, trash, debris, and sediment and are designed to drop directly into existing catch basins.
Measurable Goal(s) -Catch basins inventory completed; number of catch basins retrofitted with filtering devices and/or flow regulators.
B. Best Management Practice II (Nonstructural)
- Develop a regional growth planning process to contain sprawl development and direct new growth into previously developed areas, discouraging excessive low-density development.
- Develop green parking techniques to reduce the contribution of parking lots to the total impervious and, consequently, the amount of storm water runoff. All of the green parking techniques shall be applied in new developments and some redevelopment projects, depending on the extent and parameters of the project.
- Develop an alternative paver program that can replace asphalt and concrete and can be used for driveways, parking lots, and walkways. Alternative pavers shall replace impervious surfaces, creating less storm water runoff.
Measurable Goal(s) -The reduction in impervious surface area and the number of new green parking lots installed; and the amount of new alternative pavers installations added or replaced.
C. Best Management Practice III -BMP Inspection and Maintenance Program
Develop an inspection and repair program to maintain the effectiveness of post-construction storm water control BMPs. All BMPs shall be inspected for continued effectiveness and structural integrity at regular inspection intervals.
Measurable Goal(s) -The change in the proportion of BMPs that are well maintained as a result of inspection and maintenance.
Excerpt-Puerto Rico Aqueduct and Sewer Authority (PRASA)
RULES AND REGULATIONS FOR THE SUPPLY OF WATER AND SEWER SERVICE
SECTION 2.02 – POLLUTION PREVENTION AND WATER CONSERVATION
To meet the following objectives for pollution prevention and water conservation, the Authority may establish specific requirements for a user:
- To meet federal and Puerto Rico environmental quality standards, including sludge disposal requirements, air emission requirements, and NPDES wastewater discharge requirements;
- To reduce the transfer of pollutants from one environmental medium to another;
- To increase POTW worker safety and reduce collection system hazards from toxic or hazardous gases;
- To reduce the occurrences of interference and pass through;
- To reduce sludge management costs;
- To reduce the impacts of users’ discharges;
- To conserve flow and pollutant allocations to satisfy demands for sewer service; and
- To conserve water supply sources.
User requirements may include, but are not limited to, specific requirements in a discharge permit or authorization and the implementation of a pollution prevention or water conservation plan.
SECTION 2.03 – PRETREATMENT FACILITIES
A. General
Each user shall achieve compliance with all applicable Pretreatment Requirements. Any user required to pretreat wastewater to levels that comply with such pretreatment requirements shall provide, operate, and maintain a pretreatment facility at the user’s expense. Plans describing such facilities and operating procedures shall be submitted to the Authority for review. The review of such plans and operating procedures shall in no way relieve the user from the responsibility of modifying such facilities as necessary to produce a discharge acceptable to the Authority under the provisions of these Rules and Regulations.
B. Special Facilities for Users Discharging Wastewater Containing Lard, Fats, Oils, Grease, Sand, or Similar Substances
A trap or interceptor shall be installed by users discharging wastewater containing lard, fats, oil, grease, or settling matter such as sand, dirt, or grit, or similar material in such quantities that could cause pass through, interference or adverse effects on the collection system. Gasoline stations, restaurants, bakeries, hospitals, supermarkets, shops, and other establishments who discharge such wastewaters, shall install a trap or interceptor for collection and removal of such substances. Existing users at such establishments shall install a trap or interceptor by no later than six months after the effective date of these regulations. In order to be exempted from this requirement or to receive an extension to the compliance date, an existing user must first receive written approval by the Authority. Approval will only be granted by the Authority if the user can demonstrate that its discharge will not pass through or cause interference. For new users, installation of a trap or interceptor shall be completed before a new user shall be authorized to discharge into the sewer system. Facilities shall be properly operated and maintained by the user at the user’s expense. The user shall properly remove and dispose of materials accumulated in the trap or interceptor and maintain records of said disposal. The records shall at least provide the date, amount of material removed, and the name of the person to whom the removed material was delivered for transport and reclamation or disposal.
Failure of the user to operate and maintain a trap or interceptor properly or to maintain records of the produced and disposed material will be considered a violation of these Rules and Regulations and shall be subject to enforcement actions provided herein.
C. OPERATION AND MAINTENANCE PLAN
All users who operate pretreatment systems shall be required to develop and implement an operation and maintenance plan, to ensure compliance with these Rules and Regulations. A user’s operation and maintenance plan shall, at a minimum, include:
- Operation and maintenance manual, covering:
- Waste and wastewater sources;
- Description of treatment process units with treatment process flow diagram;
- Description of treatment process control;
- Instrument calibration procedures;
- Troubleshooting and corrective action procedures;
- Preparation and handling of treatment chemicals;
- Maintenance of log and record sheets used in relation to the pretreatment facilities;
- Maintenance schedule for equipment and instrumentation; and
- Emergency telephone numbers;
- A list of adequate operating staff duly qualified to carry out operation, maintenance, and testing functions;
- Operating log for recording operating data, maintenance performed, analytical results, and the volume of wastewater discharged to the treatment works;
- Records showing the handling of wastewater residues and sludges generated by the pretreatment facility, including waste manifests; and
- A copy of applicable licenses required by law for the operation of such facilities.
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Frequently Asked Questions
Does the Municipality of San Juan have a stormwater ordinance for new development?
San Juan’s Storm Water Management Program includes plans to develop a stormwater ordinance that would establish minimum requirements for new development and redevelopment, prohibit illicit discharges into surface waters, and require maintenance of privately owned stormwater facilities. AQUALIS can help property owners in San Juan stay current on how these requirements are finalized and applied.
What post construction BMPs does San Juan's program focus on?
The program’s post construction minimum control measure targets new development and redevelopment projects that disturb one acre or more, including smaller projects that are part of a larger development plan. Planned structural practices include dry and wet extended detention ponds, porous pavement, stormwater wetlands, grassed swales, and catch basin inserts designed to capture sediment, debris, and pollutants before they reach the storm sewer system.
Does my commercial property need a grease trap or interceptor in San Juan?
Yes, if you discharge wastewater containing lard, fats, oil, grease, sand, dirt, or similar settling material into the sewer system, under Puerto Rico Aqueduct and Sewer Authority (PRASA) rules. This applies to gas stations, restaurants, bakeries, hospitals, supermarkets, and similar establishments. Existing users had 6 months from the regulation’s effective date to install a trap or interceptor, and new users must install one before they’re authorized to discharge.
Who pays to operate and maintain a grease trap or interceptor in San Juan?
The property owner, at their own expense. You’re also required to properly remove and dispose of accumulated material and keep records showing the date, amount removed, and who received the material for transport and disposal. Failing to maintain the trap or interceptor, or failing to keep these records, is treated as a violation under PRASA’s rules.
The information on this page is provided for general informational purposes only and is not legal advice. Regulations change frequently — AQUALIS makes no warranty as to the accuracy or completeness of this content, and any reliance on it is at your own risk. Consult a qualified professional or your local regulatory authority to confirm requirements applicable to your specific property.
