AMWUA Blog

Jun 21 2021Share

Protecting our Storm Drains, Safeguards our Water

By AMWUA Staff

With monsoon season now upon us, we eagerly and desperately await the arrival of rain, which would add much-needed moisture to our arid landscape, refresh the air, minimize dust, and provide some relief to those battling wildfires.

While any amount of precipitation would be appreciated, storms that come during the monsoon season can also bring heavy downpours that create strong water flows that go over driveways and sidewalks, through streets and parking lots, increasing the chance of flooding. Unfortunately, these forceful water flows can also carry pollutants such as trash, oil, pet waste, and pesticides into our storm drain, contaminating water that eventually flows into our local washes, parks, streams, and wetlands.

Stormwater runoff is one of the leading causes of water pollution in the United States. While some of the debris is easily visible, like trash items and regular litter, the rain also transports other pollutants that are not as visible but far more harmful, like oil and grease, dissolved metals like lead and copper, and unnatural amounts of sediment from oily driveways, constructions sites, and roadways.

Storm drain vs sewer drain graphicIt’s important to note that not all water is treated equally. The cities have two separate water collection systems. The sanitary sewer system collects wastewater from sinks, toilets, showers, and washing machines that are transported through pipes and flow to treatment plants. Whereas storm drains carry water that remains untreated directly into washes, parks, and rivers. While both systems have extensive infrastructure, the stormwater system that includes everything from ditches and culverts, ponds and lakes, curbs and gutters, to wetlands and rain gardens is not part of a treatment process at any point. This is why we all must do our part to protect our water and our environment by remembering “only rain in the storm drain.”

Basic stormwater runoff facts can help us better understand the impact contaminated rainwater can have on our environment. In addition, there are valuable tips the cities provide their residents to help us all better understand the role we can play in keeping our stormwater free of contaminants, including the following:

Pet waste
Collect pet waste in a plastic bag and throw it away in a garbage can. Pet waste contains bacteria and other pathogens that are not healthy additives to our water.

Automobile Maintenance
Properly maintain vehicles to prevent fluid leaks. Use drip pans to catch leaks. Clean up leaks and spills using an absorbent such as kitty litter or sand. Sweep up immediately and properly dispose of. One quart of motor oil can contaminate over 250,000 gallons of water.

Vehicle Washing
Use a commercial or self-service car wash if possible – it is actually more water-efficient. If you choose to wash your vehicle at home, make sure you use a bucket and phosphate-free, biodegradable detergent—direct wash water to landscaping, when possible. Dispose of wash water into a sink or toilet.

Lawn Care
Use pesticides, fertilizers, and other lawn care products sparingly and following label instructions. Overwatering can carry pollutants to rivers and washes. Also, do not sweep or wash yard debris into the street. Debris can clog storm drain inlets, causing flooding.

Household Chemicals
Keep chemicals in labeled, closed containers. Leftover household chemicals, including paint, used oil, cleaners, and yard chemicals, should be appropriately disposed of or recycled. Instead, take these items to a Household Hazardous Waste site or collection event.

Spill Management
Keep absorbents, such as kitty litter, sand, or old rags on hand for cleaning up spills. Absorb spills and immediately sweep them into a trash bag and dispose of them in the garbage.

Pools and Spas
Backwash or drain your pool, spa, or water feature to the sanitary sewer using your home’s cleanout. Or backwash the water to your yard, making sure the water stays on your property. Discharging pool water to the street can contaminate and cause other problems.

Trash & Recycling
Bag and properly tie loose trash. Always keep trash and recycling bins closed.

The practice of these healthy household habits by all of us can keep common pollutants off the ground and out of our storm water. In the end, clean runoff is a community effort that begins long before it rains.


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For over 50 years, Arizona Municipal Water Users Association has worked to protect our member cities’ ability to provide assured, safe, and sustainable water supplies to their communities. For more water information, visit www.amwua.org.

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