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Splash: Flood recovery health & safety tips

Pre-flood prep and post-flood clean-up pointers from the Snohomish Health District

SNOHOMISH COUNTY, Wash. – Has high water soaked your home? Local public health wants to help you tackle the flood clean-up with your own safety and well-being in mind. Snohomish Health District’s "Emergency Flood Sanitation" tip sheet includes the "how-to’s" necessary to keep food and drinking water safe, disinfect wells, dispose of sewage and garbage, and clean up your home and belongings after floodwaters recede. The four-page handout is available for download at (search for "flood"), and at the Snohomish Health District Environmental Health office at 3020 Rucker Ave., Suite 104, Everett, Wash.

In addition to offering reliable information and advice, the Health District’s sanitarians accept water samples for coliform and water quality testing. Pick up water sample bottles at the Snohomish Health District Everett office, or at the Health District’s south county site at 6101 200th St. SW, Lynnwood. Bring the water bottles back only to the Everett site. A coliform bacteria test costs $27 payable when you bring in the water sample.

For more information, call the Health District’s Water/Wastewater section: 425.339.5250. Established in 1959, the Snohomish Health District works for a safer and healthier community through disease prevention, health promotion, and protection from environmental threats.



  1. Store emergency food, water, and medical supplies in a convenient dry place. Food should require little cooking and no refrigeration.
  2. Store water in thoroughly washed containers, such as plastic soft drink bottles. Seal tightly, label them, and store in a cool dark place. Rotate water every 6 months.
  3. Keep liquid chlorine household bleach handy for clean up and disinfecting water.
  4. Protect food freezers and refrigerators, particularly if in a basement, by raising them or removing them.
  5. If water rises, protect water supply equipment. Move the electric pump to a safe location to protect the motor.
  6. If you are evacuating, turn off all utilities at the main power switch and close the main gas valve. Don’t touch electrical equipment unless it is in a dry area.


  1. Drinking water – do not use private water systems that have been flooded until water is boiled or treated. Bring the water to a full rolling boil for 1 minute before using. Water used for brushing teeth, washing dishes, or foods requires the same treatment as drinking water.
  2. If large quantities of water are required, or boiling is inconvenient because of fuel failures, use ordinary liquid household chlorine bleach to disinfect the water. Add 1/2 teaspoon to each 5 gallons of water, or 8 to 10 drops to 1 gallon of water. Double the amount of bleach for cloudy or colored water. Allow the mixture to stand for 30 minutes before using.
  3. You will need to disinfect the well when floodwater recedes and power returns.

  • Use liquid chlorine bleach (5¼% – 6½% chlorine) in an amount equivalent to 1 gallon for each 1,000 gallons of water in the well. Do not use bleach with additives such as "fresh scent."
  • Remove debris that may have entered the well during flooding. Run the water until it runs clear. Roughly calculate the volume of water in the well: Multiply the number of cubic feet of water by 7 ½ to determine the number of gallons. (NOTE: For a 36-inch diameter casing, each foot of water equals about 50 gallons. For a 6-inch diameter casing, each foot of water equals about 2 gallons.)
  • Pour the required quantity of bleach into the well. Connect a garden hose to the nearest outside faucet and circulate the water through the hose and back into the well. This will mix the chlorine with the water and the pump will draw the chlorine to the bottom of the well. When you start smelling the chlorine in the water coming out of the hose, work the hose around to rinse the upper portion of the well with the disinfectant. (NOTE: If you cannot reach the well with a hose, rinse the upper portion of the casing by pouring chlorinated water down the inside of the case using a bucket. Mix 1 cup of chlorine bleach per bucket of water.)
  • Draw water at every water outlet connected to the system until a strong chlorine odor is perceptible. Allow the disinfectant to remain in the system overnight (24 hours is preferable).
  • Use one or more outside faucet to draw water out of the well to remove the chlorine. The well should be thoroughly and repeatedly flushed to remove the chlorine. All of the water lines should also be flushed.
  • After following this procedure and rendering the water completely free of disinfectant, you should wait a minimum of 7 days following disinfection of a drilled well prior to sampling. Wait a minimum of 14 days following disinfection of a dug well before sampling. This bacteriological analysis will indicate whether or not the underground source of water is safe for consumption.

Water sample bottles are available at the Snohomish Health District, Environmental Health Section, Suite 104, 3020 Rucker Avenue, Everett, or at the Snohomish Health District’s south county site at 6101 200th Street SW, Lynnwood. Bring the water bottles back only to the Health District’s Environmental Health office in Everett. There is a $27 fee to test the water for coliform bacteria payable when you bring in the water sample.


If you are on a public water supply and your area flooded, check with your local water district or company for current conditions. Boil your water for 1 minute if there are any signs of contamination.


  1. Destroy foods, medicines, and cosmetics packed in cardboard or otherwise not hermetically sealed which have been in contact with flood waters. This includes flour, cereal, and other commodities in bags or packages. Rinse cans in a dilute bleach solution before opening.
  2. Discard contaminated fresh fruit and vegetable products.
  3. Use only commercially pasteurized or canned milk that has not been subject to flood waters.
  4. If the refrigeration is off for more than 4 hours, some foods may become unsafe for consumption. Contact our Food Section for advice: 425.339.5250.
  5. If the power is off, use dry ice from the nearest source (such as dairies) to preserve food for many hours.
  6. If you doubt the safety of any food or drug product, throw it out.


  1. Check and pump out septic tanks if necessary after floodwaters recede. Drainfields need replacement only if they are severely damaged or eroded. 
  2. If temporary pit privies are used, add lime to the pit frequently to keep down odors and flies, and again when the pit is abandoned.
  3. Take garbage to a county drop-box or transfer station for proper disposal.


Wet or flooded fixtures and wires present a serious threat of fire or electrocution. To reduce the danger of electrical shock or fire, do not attempt to use electricity until it is thoroughly checked by a qualified electrician.


  1. Items made of wood, metal or of other hard substances, including glass and chinaware, should be thoroughly scrubbed with soap and hot water and then allowed to air dry.
  2. Thoroughly launder or dry clean clothing, bedding, and other items made of soft materials. Mattresses and stuffed furniture can’t be cleaned adequately, even with steam, and should be discarded.
  3. Dry wet-washed items for 10 hours. Whenever possible, dry the items in direct sunlight.
  4. Wash your hands in soap and water immediately after handling objects recovered from the flood areas. Keep your hands away from your mouth while cleaning or otherwise handling these items.


  1. Clear out trash and mud from buildings. You can arrange for a dumpster with your refuse collection company.
  2. Flush with clean water with a hose under pressure. Do not use river water for this.
  3. Use soap and hot water to scrub floors and walls and all other surfaces that people are likely to touch. Rinse thoroughly with clean water. Drain off water.
  4. Use a disinfectant solution (one ounce of household bleach to 4 gallons of water) after scrubbing flooded surfaces.
  5. Open all doors and windows and allow the entire building and everything in it to dry thoroughly. Do not reoccupy the building for at least 10 hours after the drying is completed.
  6. Check flues, chimneys, wiring, and plumbing.
  7. Check for weakened foundations and warped doors and windows.
  8. Floodwater may carry a variety of germs and contaminants. Wash your hands frequently with soap and disinfected water to prevent the spread of disease. Wear gloves and boots at all times.
  9. If sewage has overflowed inside the residence, refer to the Snohomish Health District’s "Guidelines for Cleaning Indoor Sewage Spills" for clean up procedures.