Safe Ash Cleanup After Wildfires

Cleaning up the ash from our homes, yards, streets and businesses will keep our community and environment healthier, but it must be done safely. The information below is for residents and businesses who are cleaning up ash, not those cleaning up burned structures. 


The storm drain system transports rainwater to local creeks, rivers, and the ocean. This system was created to prevent flooding within communities and homes.

All water and materials that enter the storm drain system are untreated.

The sanitary sewer is a plumbed system that transports used water from buildings to a wastewater collection and treatment facility, where the water and sewage is treated.

If you see an outdoor drain and are unsure of its use, assume it is a storm drain and do not discharge wash water to it.

Clean creeks are important. They provide vital fish habitat, recreation, and add to the beauty of our city.

Keeping Ash Out of Our Water

It’s important to minimize the amount of ash and debris that enters the storm drain system (e.g., streets, gutters, storm drains). Ash can easily be carried by rain, irrigation overspray, wash water, or wind into our local creeks, rivers, and ocean, where it can be detrimental to public and environmental health. The goal this winter is to prevent ash and debris from entering our waterways. You can help by taking the simple steps below to clean up ash around your residence or business.

Safe Cleanup Steps

When you determine it is safe to clean up ash, PROTECT YOURSELF and remember these three C’s: CONTROL – CONTAIN – CAPTURE


Ash can be harmful to your health and the health of those around you, with the greatest risk coming from fine suspended particles that are usually too small to see. Ash deposited on surfaces both indoors and outdoors can be inhaled, if it becomes airborne when you clean up, and may cause health issues. Avoid using cleanup methods that re-suspend ash and particulate matter in the air, such as leaf blowing. 

  • People with heart or lung disease, including asthma, older adults, children, and pregnant women should use special caution around ash. If you have any underlying health conditions talk to your doctor before using a respirator or working around ash.
  • Avoid skin contact with ash.
    • Wear gloves, long-sleeved shirts, long pants, shoes and socks to avoid skin contact. Goggles are also a good idea.
    • If you get ash on your skin, in your eyes, or in your mouth, wash it off as soon as you can.
    • Change your shoes and clothing before you leave the cleanup site to avoid tracking ash offsite, into your car, or other places.
    • Contact with wet ash may cause chemical burns or skin irritation.
  • Use a snug-fitting NIOSH N-95 or P-100 particulate respirator mask.
    • Select a respirator that has been tested and approved by NIOSH and has the words “NIOSH” and either “N95” or “P100” printed on it. These have two straps and are available online, and at many hardware stores and pharmacies.
    • Buy respirators in a size that can be tightened over your mouth and nose with a snug seal to your face. Surgical masks and one-strap dust masks will not protect your lungs. They are not designed to seal tightly to the face. 
  • Thoroughly wash any fruits or vegetables from trees or gardens where ash has fallen. Wash your hands well before eating.

2. Control

    • Leaf blowers re-suspend harmful fine particles into the air and create more health concerns.
  • Only use household vacuums or shop vacuums with HEPA filters.
    • Standard household and shop vacuums re-suspend harmful fine particles and create more health concerns.
  • Children or pets should not be nearby while you clean up ash. Do not allow children or pets to play in ashy areas.
    • Clean ash off all children’s toys and climbing structures before use.
    • Clean ash off pets.

3. Contain

  • Before sweeping indoor and outdoor hard surfaces, mist them very lightly with water to keep dust down. When you wet down ash, use as little water as you can.
  • Sweep gently with a push broom into a pile, then lightly mist with water before scraping up pile.
  • After sweeping, mop with a damp cloth or hose lightly with water into a vegetated area.
    • Take care to conserve water. Do not allow water to go down the driveway, down the street, or into storm drains. You may allow water to drain into landscaping as ash will not hurt plants or grass. 
  • Scrape ash and debris into plastic bags, seal, and dispose in the regular trash.
    • If you suspect hazardous waste, including asbestos, is present, contact your local hazardous waste authorities regarding appropriate disposal.
  • Commercial cleaning may be needed for carpets, upholstery, and window treatments, especially near high traffic entrances where ash may get tracked in. 

4. Capture

Ash has a high pH and, in large amounts, can be harmful for people, the environment, and aquatic life. It can also clog storm drains and pipes, which can cause flooding. To prevent this:

    • Divert water away from storm drains or try to filter the wash water with gravel bags, filter fabric, weighted wattles, etc., in front of storm drains. Scoop up captured ash and debris and dispose of appropriately, or vacuum with a wet/dry shop vac.
    • You can make your own water capture system by rolling up beach towels and putting them in plastic trash bags, and then laying those around the wash areas. Vacuum up water or divert into a landscape area.
    • If washing your roof, redirect downspouts to landscaped areas. 
    • Take your vehicle to a car wash or wash it over a vegetated area such as your lawn.


It is illegal to allow anything
other than rainwater to be
discharged to a gutter or storm drain.

For an emergency or a spill involving hazardous materials or hazardous waste call 911 or your local Fire Department.

For All Non-Emergency / Non-Hazardous Spills

Have you seen this in your neighborhood?