Maintenance

SMPs include systems such as bioinfiltration/bioretention basins and rain gardens, subsurface infiltration basins, green roofs, blue roofs, and blue-green roofs, media filtration devices, porous surfaces (porous pavers, reinforced turf, porous play surfaces), and porous pavement (porous concrete and porous asphalt).

All properties where SMPs were installed to comply with regulatory requirements, or to receive a credit on the monthly water bill, are responsible for maintaining those SMPs. For development projects that trigger the PWD Stormwater Regulations and stormwater retrofit projects that receive a stormwater grant, an Operations and Maintenance Agreement is recorded to the deed of the property to notify future owners of their responsibility to preserve and maintain their SMPs and site configuration.

Property owners who are intending to make modifications to site configuration or SMPs must contact PWD Private Development Services before making any modifications.

What is required of property owners?

SMPs and the areas that drain to the SMPs must be consistently inspected and maintained. The property owner is required to ensure this maintenance is completed and ensure the functionality of all SMPs. If SMPs begin to fail, the cost to regain functionality may increase substantially. Records of inspections and maintenance should be retained to submit to PWD if required.

Maintenance resources

Property owners, or individuals conducting inspections and/or maintenance on the owner’s behalf, should have a strong working knowledge and understanding of each SMP and its critical design components to effectively assess maintenance requirements. Additionally, some SMPs, such as porous pavement and subsurface systems, require special equipment and/or training to maintain.

If you are unsure who to contact for maintenance services, PWD offers a list of local contractors that perform this work. There may be other qualified contractors who can help as well. (As of 7/7/2025, a new version of the local contractor list is now available. If you have accessed the list previously, you may need to clear your browser cache to see the latest version.) 

PWD has maintenance fact sheets for each SMP type to help guide the frequency and type of maintenance required. Maintenance requirements are site specific, and the recommendations may need to be modified according to site conditions. PWD has identified some frequent maintenance issues and how to identify them. See the How to Resolve Commonly Found Issues section below for more information. 

If your property was built after July 2023, you may have an SMP Maintenance Guide including a Site Map and a separate Maintenance Schedule Form that was submitted to PWD. Contact PWD to obtain these documents or similar resources to assist in conducting SMP maintenance activities for the property.

What to expect from PWD

PWD Maintenance Inspections (Post-construction inspections)

PWD periodically inspects properties to check the functionality and maintenance of the SMPs. PWD will contact the property owner of record to schedule these inspections. After inspection, PWD will provide the property with a report detailing the results of our visit and identifying any SMPs or features requiring maintenance or corrective action.  PWD will work with the property to resolve any issues identified in the report. Report deadlines are 60 days from issuance.

Need an extension?

Opportunity for extension may be available. Contact PWDPCI@phila.gov to request a maintenance extension form. Please note that PWD may only approve one (1) extension of the original corrective action deadline, for a maximum extension of 45 days. Failure to submit the completed form by the above stated deadline may result in enforcement action.

How to show compliance

When verifying that all required corrective actions have been addressed, all documentation must be sent to PWDPCI@phila.gov prior to the corrective action deadline and include the PWD Project Tracking Number in the subject line.

Photos must be labeled by structure in accordance with the labels used in the inspection report. Photos must show before and after conditions of each component along with documentation to verify the completed work. Our email servers can only handle attachments up to 10 MB - larger photos can be submitted in .doc, .docx, .pdf or via file sharing sites.

What happens if I miss a deadline?

Failure to submit documentation properly demonstrating the resolution of required corrective actions by the communicated deadline may result in enforcement action, and consequently fine accruals, as described below.

PWD Enforcement (Post-construction enforcement)

PWD will issue corrective actions in an enforcement letter. Within 30 days, a corrective action plan (CAP) must be submitted indicating the proposed actions and an anticipated completion date to complete the corrective actions. Certain site conditions may warrant immediate escalation to a Notice of Violations and Order to Correct (NOV), which requires the completion of all corrective actions within 30 days.

Need an extension? 

Opportunity for extension may be available. Contact the enforcement case coordinator prior to the deadline if more time is required. PWD is under no obligation to provide an extension, and extensions may not be permitted under certain circumstances (e.g., extensions are typically not available once a property has received a Notice of Violation (NOV)).

How to show compliance 

Photo documentation and a Declaration of Completed Corrective Action (DCCA) must be submitted to the enforcement case coordinator.

Include clear and labeled photographs (before and after maintenance or repair) that identify the SMP, structure, and corrective action addressed. Construction-related repairs or modifications that require measurable changes must be documented in photographs with a measuring device. Unlabeled photos may not be accepted. A sketch or record drawing may also be required for construction-related repairs. 

Our email servers can only handle attachments up to 10 MB - larger photos can be submitted in .doc, .docx, .pdf, or via file sharing sites.

What happens if I miss a deadline? 

Failure to comply with communicated deadlines may result in the issuance of a NOV, daily fines, suspension of applicable stormwater credits, a Stop Work Order, a court order, abatement by the City and billing for expenses (including administrative expenses), and/or the withholding, suspension, or revocation of any stormwater approvals.

Such penalties are cumulative and do not prevent the City from pursuing all remedies available in law or equity. PWD may enforce any available penalties at any time until all enforcement violations are sufficiently resolved.

Corrective action requires a post-construction field change 

In some cases, re-design of stormwater management systems (post-construction field change) may be required if SMPs have failed and functionality cannot easily be restored to the intended design through maintenance. PWD will communicate this requirement in a corrective action.

A scope of work and schedule to complete various milestones throughout the re-design process will be required. Field change plans, SMP maintenance guide, revised Operations and Maintenance (O&M) Agreement, and a record drawing may be required. 

Refer to Chapter 2.3 and Appendix E, Appendix F, and Appendix G of the Philadelphia Stormwater Management Guidance Manual for field change submission requirements. Note that the described Expiration Policy does not apply. All enforcement deadlines will be based upon the submitted schedule and any other communication provided by PWD.

Field change submissions may be emailed directly to the assigned Enforcement Coordinator or uploaded through the Plan Review Dashboard, using the “Field Change” submission option (if the project tracking number starts with FY).

Need help?

Questions regarding Post‑Construction Inspection reports or other communications can be submitted via PWDPCI@phila.gov.

Questions regarding Post-Construction Enforcement reports or other communications can be directed to the assigned enforcement case coordinator listed in the enforcement documentation or you may call (215) 686‑9445. 

To best assist you, please provide the property address, PWD tracking number (if available), and any documentation you may have received from PWD noting inspection or maintenance requirements.

How to resolve commonly found issues

Disclaimer: Maintenance activities can vary largely, from picking up leaves from an inlet grate to requiring professional knowledge and specialized equipment. Under no circumstances should a non-stormwater-professional physically enter a stormwater structure to complete maintenance activities. Owners should consult with a stormwater maintenance professional on how to properly and safely perform all maintenance activities.

Clogging

It is common for trash, sediment, and debris to block and potentially clog a structure designed to intake stormwater, such as a yard/area drain, inlet grate, or inlet pipe. As part of regular ongoing maintenance activity, inlets should be inspected after several storms to ensure they are functioning properly, and remove all trash, sediment, and debris at least twice a year, and on an as-needed basis.

Depending on the extent and accessibility of the trash, sediment, and debris, manual removal may be feasible ensuring proper safety precautions are taken (i.e., following confined space entry protocols), or mechanical removal may be required by a stormwater professional.

Basin not draining within 72 hours of a rainfall event

Stormwater management practices (SMP) are designed to treat, intake, and infiltrate or detain and release stormwater runoff within 72 hours of a rainfall event. If the SMP does not drain within that timeframe, the SMP is considered as failed. Depending on the extent of failure, maintenance, complete replacement, or design and construction of an alternative stormwater management strategy may be required. See the Corrective action requires a post-construction field change section for more details. 

Disposal of groundwater and/or accumulated stormwater to the City sewer and/or hauling water offsite requires a permit from the Industrial Waste Unit.

Erosion

Bioinfiltration/bioretention basins, and pervious areas designed to disconnect adjacent impervious area should be inspected for sediment build-up and erosion on a quarterly basis.

If erosion has occurred, the bare soil areas should be stabilized with vegetation or other appropriate stabilization measures, consulting a stormwater maintenance professional.  For additional information, refer to Chapter 4.13.5 Landscaping Construction Guidance of the Philadelphia Stormwater Management Guidance Manual.

Porous surfaces

Porous asphalt, porous concrete, and other porous surfaces are prone to clogging and require frequent maintenance activity. Refer to the porous surfaces section of the Philadelphia Stormwater Management Guidance Manual for suggested maintenance frequency and activities for porous surfaces (porous pavers, reinforced turf, porous play surfaces).

Ongoing maintenance activity for porous asphalt and porous concrete suggests a professional stormwater maintenance provider vacuum the porous asphalt or concrete surfaces with a regenerative air sweeper or commercial vacuum sweeper on a quarterly basis. Although, if the site produces more than an average amount of sediment, like a high traffic parking lot, loading dock, material storage facilities, junk yards, waste collection and disposal sites, and so on, more frequent vacuuming will likely be required to maintain porous functionality.

To retain compliance, porous asphalt and porous concrete must maintain an infiltration rate of at least 10 inches/hour. Infiltration testing should be conducted according to ASTM (American Society for Testing and Materials) c1701, Standard Test Method for Infiltration Rate of In Place Pervious Concrete.

During their inspections, PWD Inspection and Enforcement teams will conduct infiltration testing following ASTM standards testing, documenting their results, which can be shared upon request. Porous SMP infiltration rates that do not meet these minimum requirements will be required to restore the SMP back to functionality though the PWD enforcement process. Depending on the extent of failure, vacuuming, complete replacement, or design and construction of an alternative stormwater management strategy may be required. See the Corrective action requires a post-construction field change section for more details.

Weir walls

Outlet control structures typically consist of concrete boxes that contain one or more outlet controls such as orifices or weirs. Weirs are engineered barriers/dams designed to control the release of stormwater from SMPs to the sewer.

To function as designed, the weir wall must be watertight along the edges, preventing water from leaking around the weir wall before flowing through an orifice or over the weir wall.

As part of regular ongoing maintenance activities, the outlet control structures must be inspected after several storms to ensure that water can pass freely through any orifices and that the weir wall is not leaking. Leaks can often be detected through visual inspection by observing gaps between the weir wall and structure wall and also by measuring the distance from the ground surface to the top of the water on either side of the weir wall. Equal measurements may be indicative of a leaking weir wall. Dye testing may also be completed if a leak is suspected.

When a weir wall is found to potentially be leaking during a maintenance inspection, the issue must be addressed. The site will be required to consult a stormwater management professional to either seal the bottom and sides of the weir wall to the interior of the outlet control structure or dye test from the inflow side of the weir wall to determine where a leak is present, and if one is, seal that section of the weir wall. Regardless of which method is utilized, submittal of photo and video documentation to PWD will be required to demonstrate that the weir is properly sealed.

Non-stormwater accumulation or discharge

Any substance that is not stormwater is not designed to enter the stormwater system. Sediment, trash, and debris is typically prevented from entering stormwater systems through various pretreatment devices and can be eliminated through typical maintenance procedures. Through inspection, more egregious issues may be identified and must be eliminated by other means than standard maintenance procedures. In all circumstances, a qualified professional will be required to investigate and identify the source and propose a plan to eliminate the issue.

Documentation must be submitted to PWD that includes, but is not limited to, the following: 

• Clear identification of the source of the identified issue 
• Detailed scope of the proposed engineering solution to resolve the identified issue for PWD review 

Following construction, submit documentation demonstrating the resolution of the identified issue. Record drawings may be required. 

Dry weather discharge

Stormwater management practices are designed to treat, intake, and infiltrate or detain and release stormwater runoff within 72 hours of a rainfall event. When water is observed actively flowing into or out of the system greater than 72 hours after a rainfall event, this is considered “dry weather discharge.” This could be caused by a smaller scale issue like rooftop ponding or HVAC drainage that may not require resolution, or a larger scale issue like a cross connection with a sanitary line (see Sanitary Waste). In either case, the source must be identified and any resolution required pursued according to PWD instruction.

Sanitary waste

Whether sanitary waste is identified as dry weather discharge (see Dry weather discharge), is observed to be present within the stormwater system without active discharge, or is a result of backflow from the combined sewer, this condition must be eliminated. 

Any sanitary waste found in a stormwater system must not be flushed through the system to the outlet structure and left to discharge to the sewer by gravity.  Hauling contaminated stormwater offsite requires a permit from the Industrial Waste Unit.