How our City keeps trash out of waterways

How our City keeps trash out of waterways

Published on September 22, 2025

Menlo Park's streets are connected to waterways through storm drains. Now that the rainy season is upon us, rain will flow into the storm drains and collect any pollutants found on surfaces like roofs, driveways, sidewalks and streets. Unlike wastewater, stormwater is not treated before it enters waterways. In Menlo Park, pollutants flow into our creeks and San Francisco Bay. Over time, pollutants in these waterways concentrate, affecting water quality and impacting our beaches and aquatic life.

The state of California addresses these water quality issues through the Municipal Regional Stormwater NPDES Permit (MRP). The MRP is a comprehensive permit that regulates activities related to construction sites, industrial and commercial sites, illegal discharges and illicit connections, new development, and municipal operations. Like other cities in the San Francisco Bay Area, Menlo Park is required to comply with the MRP. The information below describes how Menlo Park takes steps to ensure compliance with the MRP and protection of our natural resources:

Construction
Menlo Park requires construction sites to prevent pollution by containing spills, mitigating erosion and safely storing materials to keep the storm drains clear. Larger or high-priority sites that plan to construct during the wet season are given a special designation. This designation is called a "C.6. Construction Site." The wet season occurs from September to April each year. Projects with this special designation are subject to monthly inspections during the wet season to ensure that the contractors are complying with pollution prevention methods, otherwise known as best management practices (BMPs). While C.6. construction sites are subject to inspection during the wet season, all construction sites are required to follow BMPs throughout the year.

Industrial and Commercial Sites

Food handling facilities such as restaurants, institutional cafeterias, grocery stores, bakeries and delis can contribute to stormwater pollution, mainly through improper cleanup practices that allow food particles, oil, grease and cleaning products to flow to a street, gutter or storm drain. Because of this risk, the MRP requires Menlo Park to develop a business inspection plan for commercial and industrial sites. During facility visits, contractors ensure that businesses follow best practices for food service facilities. These businesses are inspected once every 5 years.

Commercial sites also include auto body shops. In these shops, oil, grease, antifreeze and other toxic automotive fluids may be produced. It is imperative that these fluids are properly managed to prevent entry into the storm drain. Have you ever experienced a clogged sink due to buildup of oil and grease? Imagine that in our waterways! These businesses are inspected once every 3 years. Other commercial sites may also be inspected, given their likelihood of producing stormwater pollutants. Flows to Bay has resources for other commercial businesses.

Industrial and manufacturing sites pose potential environmental hazards when practices are not followed. Menlo Park staff inspect these facilities annually. In addition to complying with local stormwater ordinances, manufacturing facilities and certain other industrial facilities are required to notify the State Water Resource Control Board that they understand they are subject to the general permit and commit to identifying and implementing BMPs needed at their facility to prevent stormwater pollution to the maximum extent practicable. The State Water Resources Control Board has guidance for identifying whether a business is subject to the State Industrial General Permit and preparing a Stormwater Pollution Prevention Plan. The local sanitary sewer treatment authority may also have restrictions on discharge into sanitary drains. West Bay Sanitary District serves most Menlo Park businesses.

Illicit Discharges

An illicit discharge occurs when prohibited dumping or spills end up in the storm drain. Help keep our storm drains clean, and fill out the illicit discharge form if prohibited materials enter the City storm drain system.

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