Stormwater Program
Frequently Asked Questions
What is stormwater?
Stormwater, or urban runoff, is the water that flows from properties into the gutters and storm drains when it rains. Stormwater should be mostly rainwater, but it also contains water from irrigation, car washing, chlorinated pool water, and any pollutants (like pesticides, herbicides, fertilizers, trash, grass clippings, leaves, sediment, animal wastes and oils) that may be carried by the water as it flows across paved surfaces and landscapes. This water flows into one of over 2,600 storm drain inlets located along street gutters and in private parking lots to enter the City's storm drainage system.
What is stormwater pollution?
Stormwater pollution occurs when pollutants from sources such as automobile fluids, sediment, chlorinated spa and pool water, and plant material are poured or washed down storm drains. Storm water pollution can also simply happen when rain water picks up pollutants (such as trash, oil, fertilizers and pesticides, sediment, and other materials) as it flows across paved surfaces and landscapes and carries them into the stormwater conveyance system and out to local waterways.
Why is it important to maintain the quality of our stormwater?
Storm drains lead directly to receiving waters (e.g., our local rivers, creeks, wetlands, sloughs, and eventually, the ocean). Unlike sanitary sewers that direct water to a wastewater treatment facility before being discharged to a local water body, stormwater is discharged untreated. Any pollutant (e.g., trash, yard waste, sediments, pesticides, fertilizers, human and animal wastes, and other chemicals) that it carries is transported and dumped into receiving waters affecting the water's physical and biological characteristics. The result is impairment of the quality of our water resources and of the aquatic habitat for many fish, wildlife, and organisms.
Why is it important to manage the quantity of our stormwater runoff?
Soil compaction and increasing areas of impervious surface (e.g., pavement, parking lots, buildings, and sidewalks), directly resultant from urban development and construction, often prevent water from being absorbed into the ground if not designed correctly. The result is more stormwater runs from the watershed and less water is absorbed into the ground. This increase in storm event runoff may lead to an increase in the velocity of the stormwater runoff. This may increase the risk of flooding, damage to infrastructure, and channel erosion. Flooding and erosion increases the sediment loading in the receiving water, impairing its quality.
What is the city doing to maintain the quality and manage the quantity of our stormwater?
The City of Davis has developed a Storm Water Management Plan (SWMP) to address stormwater issues within the City's jurisdiction. The SWMP is a 5 year plan to address and manage activities and development conducted in the city that are potential sources of pollutants, and which may increase the flow of stormwater. The city reviews new development to encourage "low impact" design into projects. These measures may include those which retain stormwater on site and remove contaminants from water that is discharged. The City also reviews its own operations to ensure that the best management practices known today are incorporated into its own operations and activities.
Are the sanitary sewer and storm drain systems the same thing?
Sanitary sewers and storm drains are not the same thing.
Sanitary sewers collect wastewater from indoor plumbing such as toilets, sinks, washing machines and floor drains. This "wastewater" flows to our Wastewater Treatment Plant located near the Yolo County Central Landfill and Davis Wetlands. From there it is pumped into Willow Slough and Yolo Bypass.
Storm drains transport rainwater, which never receives the advanced treatment that our wastewater receives at the Treatment Plant. From our street and storm drain inlets, this water simply flows to local area ponds, Putah Creek, and Willow Slough.
Do drain inlets get cleaned out?
There are over 2,600 drain inlets (DIs) in Davis. The City inspects every DI each year to clean them and repair any damage. Residents can help keep the stormwater conveyance system clean and fully functional by preventing leaves, sediment, and trash from flowing into and clogging up drain inlets. Plastic bags are especially bad. If you should find a clogged or damage DI, please call Public Works at 757-5686.
If yard clippings and leaves are natural, why are they considered pollutants?
Bacteria naturally decompose yard clippings and leaves, or any organic material. During this process the bacteria deplete water of dissolved oxygen, causing other aquatic organisms, like fish and aquatic plant life, to suffocate.
Organic material may also carry with it pesticides, herbicides, and fertilizers. The pesticides and herbicides can cause aquatic toxicity and the fertilizers will encourage excessive algae growth, depleting the oxygen in the water.
Find out how to properly dispose and compost your yard waste.
What is an illegal discharge?
An illegal discharge is any non-permitted or non-exempt discharge of pollutants to the stormwater conveyance system. Pouring or washing carpet cleaning water, motor oil, pesticides, chlorinated pool or spa water, household chemicals or cleaners, paints, or any other materials into gutters and drain inlets is considered an illegal discharge. These discharges will be harmful to the environment. Those responsible for illegal discharges may be subject to fines and even imprisonment. If you see someone in the act of an illegal discharge, call Public Works at 757-5686 or dial 911. If you find evidence of an illegal discharge, please call Public Works, even during weekends. The sooner an illegal discharge gets cleaned-up the better!
What is an illicit connection?
An illicit connection means any physical connection to the storm drain system which is not expressly authorized by the City. This could be a pipe that drains the holding tank of a recreational vehicle or drains from an equipment washing area. Like illegal discharges, these discharges will be harmful to the environment. Those responsible for illicit connections are subject to fines and even imprisonment. If you should see someone with an illicit connection, please call Public Works at 757-5686.
What do I do if I see someone dumping, oil, trash or other pollutants into drain inlets?
If you see someone dumping oil, trash, or other pollutants into storm drains, or just on the ground, and as long as it does not endanger yourself, please report the location of the dump and what pollutant(s) were dumped to Public Works at 757-5686 or dial 911. This dumping is an illegal discharge and will be harmful to the environment. Those responsible for the dumping may be subject to fines and even imprisonment.
Where can I take hazardous materials, including paint, automotive fluids, that I need to dispose of?
Hazardous materials can be taken to the Yolo County Central Landfill on Household Hazardous Waste Drop-off Days. Used motor oil can be recycled for free every day at the County Landfill and selected local automotive businesses here in the City. Not sure if something is hazardous waste? Check out the City of Davis Recyclopedia to find out how to properly dispose and/or recycle hundreds of items.
What do I do if there is flooding in my neighborhood during a storm?
Most of Davis sits outside the 100-year flood zone. Serious flood events are unlikely. However, if local flooding in the streets in your area should occur, contact the City's Public Works Department at 757-5686. The City can come out and clear obstructions in the storm drain inlets or pipes. FEMA offers flood preparedness information on their website.
What are the laws and regulations about storm drains and pollution prevention?
Most laws and regulations are set up to regulate municipal operations like the City of Davis, businesses, and industrial and commercial activities. There are no direct laws that apply to residential properties at this time.`
