Q & A

Q. What is a storm drain?

A. A storm drain, storm sewer is designed to drain excess rain and ground water from paved streets, parking lots, sidewalks, and roofs. Storm drains vary in design from small residential dry wells to large municipal systems. They are fed by street gutters on most motorways, freeways and other busy roads, as well as towns in areas which experience heavy rainfall, flooding and coastal towns which experience regular storms.


Q. Is there a difference between the storm drain and sanitary sewer system?

A. The storm drain and the sewer system are separate mechanisms. Stormwater and all the pollutants that flow from our homes, parking lots, and streets go into the storm drain, and are discharged directly into our creeks and other water bodies without being treated. Water and pollutants that flow into the sanitary sewer system, such as water from our bathtubs and toilet, are sent to a wastewater treatment facility before the water is discharged to the Bay, Delta, or ocean.

Contra Costa Clean Water Program,

Q. What is a Municipal Separate Storm Sewer System (MS4)?

A. The regulatory definition of an MS4 (40 CFR 122.26(b)(8)) is “a conveyance or system of conveyances (including roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, man-made channels, or storm drains): (i) Owned or operated by a state, city, town, borough, county, parish, district, association, or other public body (created to or pursuant to state law) including special districts under state law such as a sewer district, flood control district or drainage district, or similar entity, or an Indian tribe or an authorized Indian tribal organization, or a designated and approved management agency under section 208 of the Clean Water Act that discharges into waters of the United States. (ii) Designed or used for collecting or conveying stormwater; (iii) Which is not a combined sewer; and (iv) Which is not part of a Publicly Owned Treatment Works (POTW) as defined at 40 CFR 122.2.”

In practical terms, operators of MS4s can include municipalities and local sewer districts, state and federal departments of transportation, public universities, public hospitals, military bases, and correctional facilities. The Stormwater Phase II Rule added federal systems, such as military bases and correctional facilities by including them in the definition of small MS4s.



A. Stormwater runoff is generated when precipitation from rain and snowmelt events flows over land or impervious surfaces and does not percolate into the ground. As the runoff flows over the land or impervious surfaces (paved streets, parking lots, and building rooftops), it accumulates debris, chemicals, sediment or other pollutants that could adversely affect water quality if the runoff is discharged untreated. The primary method to control stormwater discharges is the use of best management practices (BMPs). In addition, most stormwater discharges are considered point sources and require coverage under an NPDES permit



A. OSHA defines a Confined Space as an area that is large enough to enter and work, has limited means for entry and exit and is not designed for continuous occupancy.  A Confined Space Entry Permit is required for entry into a confined space that has at least one of the following:

  • Potential for hazardous atmosphere
  • Potential for engulfing an entrant
  • Internal configuration capable of trapping or asphyxiating an entrant
  • Other safety or health hazard

Confined spaces sometimes must be entered for repairs, inspection, and maintenance.  If you have to enter permit-required confined spaces on campus, you may encounter extremely hazardous atmospheric conditions and/or access difficulties that can result in injury or death.  Examples of locations which fall into this category include:  sewers, tanks, boilers, crawl spaces, vaults, storm drains, pipelines, bins, ducts, vessels, acid pits and tubs.  Each time you go into a confined space, it must be evaluated by your supervisor before you enter.  This is necessary to determine the hazards involved and the appropriate safety measures and controls that must be taken for your safety.  Death can result if you enter a confined space without using the necessary safety procedures.

Occupational Safety and Health Administration,


A. Many individuals who are unfamiliar with the importance of recycling used oil are unconsciously harming the environment by throwing it away with their normal garbage or emptying their used oil into storm drains. Such actions, especially emptying used oil into storm drains, can cause real harm to the environment. To put it into perspective, just one gallon of used oil can contaminate 1 million gallons of water.  Used oil can be re-refined into base stock for lubricating oil.

Recycling your used motor oil keeps it out of our rivers, lakes, streams and even the ground water. In many cases, that means keeping it out of our drinking water, off our beaches, and away from wildlife. We all share the responsibility of protecting our environment and keeping our waters safe. Recycling used oil allows us to continue to enjoy what many of us take for granted every day – clean water.

Most local jurisdictions provides convenient collection sites for the purpose of keeping used motor oil out of our waterways and ground water supplies and getting used oil into the recycling system.

American Petroleum Institute,


A. Waste antifreeze should never be discharged to storm sewers, septic systems, waterways, or be discharged on the ground. While used antifreeze is not a listed hazardous waste under Federal regulations, it can be classified as a characteristic hazardous waste due to the presence of metals and/or other contaminants.


Ethylene glycol, the main ingredient of all major antifreeze brands, has long been known to be poisonous. Ethylene Glycol has a sweet smell and taste which is attractive to children and pets and is highly toxic. Drinking ethylene glycol will result in depression followed by heart and breathing difficulty, kidney failure, brain damage and even death. Used antifreeze may also contain metals, such as copper, zinc, and lead. All antifreeze, new and used, must be safely stored in order to avoid tragic consequences.

Improperly disposed antifreeze can flow into waterways where it can kill fish and other animals. It can seep through the soil and into the groundwater.


Water Pollution

The ocean provides so much for us – food, medicine and much of the oxygen we breathe. Today, the ocean is facing grave threats from pollutants that enter the ocean and not only harm marine life but directly impact humans.

Take Action Against Water Pollution

You have the power to turn the tide and make everyday changes that will help prevent pollutants from reaching our ocean.

  • Keep trash and chemicals out of storm drains. This includes pet waste. Storm water from storm drains flows into the sea carrying pollutants which can lead to beach closures.
  • Plant a native plant garden. Native plants can help you reduce the use of water and fertilizers.
  • Avoid use of chemical fertilizers, instead make your own mulch and use organic fertilizers only when needed.
  • Recycle used motor oil. Don’t let motor oil spill on the ground because rain will wash it into the storm-water drains, and from there out to sea, where it can harm or kill marine life. Find an oil-recycling center near you.
  • Dispose of household cleaners properly. Household cleaning products, paint, pesticides, fluorescent light bulbs, and batteries pose a threat to water quality.Find more information about free collection centers.
  • Take the pledge. Return the favor by taking our pledge to protect the ocean.
  • Click here for more ways you can take action against water pollution.



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