Preventing Pollution at Home

Sprinkler system runs in a yard

Keeping our water clean

Clean water means healthier waterways, habitats and people. We can all take simple measures to help to reduce water pollution.

Reduce the Use of Lawn and Garden Chemicals

Common chemicals used to fertilize and control bugs often contain chemicals that are harmful to waterways. These chemicals soak into the ground and contaminate groundwater or run off into storm drains and into local streams, rivers and lakes. If you use chemicals, always follow directions on the label. Properly dispose of leftover chemicals with other household hazardous waste.

Pick Up After Your Pets

We often don’t think about the waste that our pets leave behind. Pet waste doesn’t just decompose. It adds up and contributes harmful bacteria and nutrients to local waterways when not disposed of properly. Bring a plastic bag on your next dog walk; it’s easy to pick up pet waste and place in a trash bin. Help do your part, be a good neighbor and keep our waterways clean.

Dispose of Chemicals Properly

Remember to use and dispose of chemicals wisely! Never pour household hazardous waste down the drain, onto the ground or into a storm drain. This could contaminate soil, groundwater or nearby streams and rivers. A lot of the common products used at home contain hazardous and toxic chemicals. Here is a list of some of the most common products and proper disposal options: motor oil, pesticides, leftover paint, household cleaners, medicines and car wash residue.

Properly Dispose of Unused Medications

Unwanted or unused medication should never be flushed down the toilet or dumped down the drain where they can harm the environment. When unused or unwanted medications are not disposed of properly, they can impact aquatic environment, especially fish. Recent studies show that pharmaceuticals are showing up in waterways and drinking water. Find resources on where you can dispose of leftover medication.

Don’t Drip and Drive

Got a leaky car but not sure what to do until you can get it into the shop? Prevent pollution by keeping drips and leaks cleaned up when you’re parked at home. Oil doesn’t dissolve in rain water and a little bit can travel a long way to reach and pollute our streams and groundwater. Here’s how to keep it clean:

  • Use a dry absorbent, such as some types of kitty litter, to soak up oily spots or green antifreeze puddles.
  • Try using a spill pan or drip sheet under your car to collect your leaks. Or park over a dry piece of cardboard until you can get to a shop and get it repaired.

To report spills, dripping oil or oily sheen on public streets, call Public Works Operations Services at 360-487-8177. For urgent concerns after hours, please follow the prompts.

Maintain your Septic System

Many households use septic systems for the treatment of their wastewater. When functioning properly, the wastewater is treated by your septic tank and drain field before it filters into the ground. It is important to properly maintain your septic system. Improperly functioning or failing septic systems do not adequately treat sewage leaving your home. This untreated sewage can create a health hazard and pollute local waterways. Do not flush medications or dump paints or lawn chemicals down the drain. Keep your drain field maintained; do not cover with sheds, patios or tree plantings that can damage pipes. For more information on septic system maintenance, visit the links below:

Pressure Wash the Proper Way

Waste water from pressure washing can contain pollutants such as metals, oils, paint, cleaners and dirt. Follow these steps to make sure pollutants are not carried from streets and your property to the nearest creek, lake or river. Divert the wash waste water to a sink, lawn or landscaping. Please don’t let it enter storm drains or ditches.

Before Pressure Washing

  • Absorb oil spots with kitty litter (or other absorbent) and sweep it up.
  • Sweep up trash, debris and dirt.
  • Plan a method for disposing of your waste water.

While Washing

  • Use less water: the more you use the more you move.
  • Avoid hazardous cleaners (such as those containing bleach hydrofluoric acid, muriatic acid, sodium hydroxide, etc.).
  • Water without cleaners may be discharged to a lawn or landscaped area where the water can soak into the ground without running off.
  • After washing, dump waste water into a utility sink or private sewer cleanout.


  • Only rain down the drain!
  • Never dump waste water on streets, pavement, into storm drains or ditches.
  • Never pressure wash lead-based paint.
  • Protect your septic by not dumping pressure wash waste water into your system.

Hiring a Contractor

If you’re planning to have your carpets cleaned, your home painted or your driveway washed, before you sign an agreement make sure your contractor will be properly disposing of the waste. Questions to ask of contractors in advance of pressure washing:

  • Do they regularly collect wash water and carpet cleaning waste as part of their work? If yes, where are they planning to dispose of this wastewater?
  • Do they clean up any moss or paint chips left on your yard after powerwashing or painting? If yes, how?
  • What type of cleaners, if any, do they plan to use?
  • How will they wash out any brushes, rollers, or other equipment after the work is done?
  • Never dispose of cleaning waste or wash water from paint brushes/rollers in the public street or in stormwater drains.
  • Use a ground cloth to capture paint chips and drips. Sweep up any loose chips and dispose of them properly.
  • When power washing, collect moss and fir needles and put them in the trash.
  • Use only cold water to rinse down your patio or driveway and do not use bleach or peroxide-based cleaners, which can damage pipes and harm wildlife. Even biodegradable and “non-toxic” cleaners are prohibited in our stormwater drains.
  • Whether using a contractor or doing the work yourself, you are responsible for protecting our waterways from pollutants. Remember: Only rain down the drain.

Moss Removal

Moss thrives in the Pacific Northwest courtesy of our rainy, mild winters. When you use moss-killing chemical treatments on your roof, those chemicals don’t just stay there. Rain that runs off your roof ends up in our streams or groundwater untreated, and the chemicals that kill moss can also kill fish.

Tips for dealing with moss:

  • Prevent moss where you can by trimming trees, removing leaves and fir needles, and using a dry brush. Doing this in summer will reduce the impacts to runoff from of our rainy winters.
  • If using a moss-prevention product, try to find the least toxic option possible and carefully follow the instructions on the label.
  • Never use laundry detergent, peroxide or soaps on your roof. These products won’t just stay on your roof or property. As soon as it rains, they are carried into gutters and downspouts which then flow into nearby streams, adding pollution and harming fish and wildlife.

Pools and Hot Tubs

Need to drain your pool or hot tub? Do it right to protect our streams and groundwater.

Things to consider when maintaining your pool or hot tub:

  • Always use a sanitary sewer connection or cleanout, if you have one.
  • Never drain pools or hot tubs into a septic system.
  • If you don’t have sanitary sewer access, let chlorine degrade by leaving the pool or tub uncovered in the sun, then drain slowly through landscaping.
  • About a week before you plan to drain your pool or hot tub, uncover the top, stop chemical treatment and turn off the heater. Use test strips to check for chlorine (must be 0.10 ppm or less) and pH (must be between 6 & 8), then slowly drain off the water. Never drain on a neighboring property or directly into the public street.

Keep Riparian Areas Healthy

If you have a stream in your backyard or neighborhood, you have probably noticed how waterways react when we get large rainfall events. Streams often become muddy, erode unstable banks and cause local flooding. Trees and vegetation are critical in these areas. They hold stream banks together and provide a filter for the extra water during rain and intense storm events.

Ways to promote a healthy riparian corridor in your backyard stream:

  • Avoid mowing land that is adjacent to the stream
  • Plant native plants and trees
  • Use chemicals cautiously
  • Fence livestock and animals out of riparian areas

Private Stormwater Facilities

Do you know where the storm drains in your neighborhood go? Sometimes, the storm drains have been set up so rain runoff flows directly to our creeks and rivers. Often, however, they make a stop at a biofiltration swale or other stormwater facility first. If you have a stormwater facility in your neighborhood, it may look like a grassy, wide ditch or it may be a rain garden with plantings such as grasses and shrubs.

Some neighborhoods even have private ponds for their runoff. If you have one of these in your neighborhood, maintenance usually falls to the Homeowner’s Association and may be part of the common areas tended by a landscaping company.

The most important part of a neighborhood stormwater facility is keeping it working for flood control and water quality. For maintenance tips and photos to help with proper care of your stormwater facility, please visit You’ll find videos, troubleshooting tips and fact sheets to share with neighbors.


If you have questions about other steps you can take at home to keep waterways clean, email