Fire Disaster Response - Water Wells

Fire Disaster Response Banner

As an owner of a private domestic water well that may be damaged by a wildfire, you may have some concerns about fire related impacts to your well water system.

Fire in a rural, woodsy area

The County of Santa Clara Department of Environmental Health (DEH) recommends the well owner perform a visual inspection of their well and water system, including the piping and plumbing that provide water to and throughout your home. Items that you should check include:

  • Damaged and melted or exposed electrical wiring
  • Damaged and melted PVC casing, liner or pipe
  • Damaged well houses, pressure tanks and equipment such as chlorinators, water treatment equipment and electronic controls
  • Damage to pressure tanks which could have been caused by exposure to excessive heat
  • Damage to storage tanks, vents, and overflow pipes
  • Debris, such as ash and sediment entering uncovered wells or storage tanks.

Exposed electrical wiring to the well poses a significant electrical safety hazard with potential for an electrical short to the metal casing. If the electrical wiring has been damaged by fire, do not handle the wiring or touch the casing.

If your well has been damaged by fire, contact a local licensed and bonded well constructor or pump installer to determine the extent of the damages and what must be done to either repair or decommission the well. If you think a fire may have damaged your water supply, bring bottled water back with you when you return to your home. 

Damaged well casing or plumbing should at minimum have a bacteriological test for presence of Total and Fecal Coliform.  It is also recommended to test the well water for presence of Benzene, which may have leached from the melted plastics.  If the well is near a waterway that flows from the affected fire zone, the water should additionally be tested for heavy metals, including but not limited to: Aluminum, Antimony, Arsenic, Cadmium, Selenium and Lead as well as, semi-volatile organic chemicals such as, Polynuclear Aromatic Hydrocarbons.

Inside Your Home

To the extent you can, visually check the water-supply system, including plumbing, for any damage, signs of leaks, or changes in operation. You should check to see if your well and plumbing system maintained positive pressure during the fire. This can be done by simply turning on a faucet in the household to see if water flows. You should not hear any air being released from the faucet. The flow of water should be steady and uninterrupted. If you do hear air escaping from the faucet with water intermittently spurting out when it is turned on, that is an indication that your well and household plumbing had a loss of pressure and may have been damaged.

If You've Had Loss of Water Pressure

If your visual inspection shows that there was a loss of pressure or the water system has been damaged, it is likely that your water may be contaminated with bacteria. Damaged components should be repaired or replaced. Anytime a water system loses pressure, the water should be tested for the presence of bacteria before it is used for drinking or cooking. Anytime the well or water system is repaired, it should be disinfected after a repair is made and then tested to ensure the water is safe for drinking or cooking.

Testing Your Well

When testing drinking water for the presence of bacteria or inorganic contaminants, it is necessary to collect a sample and deliver it to a CA-certified laboratory. For more information on CA-certified laboratories, visit the Division of Drinking Water Environmental Laboratory Accreditation Program webpage. You can also go to the Santa Clara Valley Water District list of certified laboratories located in Santa Clara or San Benito County or your local Yellow Pages under “Laboratories – Testing.” Samples must be collected in an approved container provided by the laboratory. When collecting a sample, follow the instructions that come with the bottle and return the sample bottle to the laboratory in the recommended time.

Using Your Water While You Wait for Test Results

You can use your water for showering and flushing toilets. Take care to avoid swallowing water from showers or baths. You should not use your water for drinking or cooking purposes unless you have boiled or disinfected it. This caution includes not washing dishes or other cooking utensils in it. While you are waiting to receive the results of bacteria testing, you can boil the water you will be using for drinking and cooking for at least 1 minute at a full rolling boil.  Boiling will not treat for suspected chemical inorganic contaminants.

Well Disinfection

You can also disinfect your well and water system while waiting for sample results. If the well tests positive for the presence of coliform bacteria, you should have the well and water system disinfected. Instructions for disinfecting wells can be found below.  Additional information may be found at our Drinking Water Program Website.

Wells must be maintained to prevent health hazards. Take steps to ensure your water is safe to drink after an emergency.

Disinfection of Private Domestic Water Wells

  • Disinfection of a well is recommended to eliminate disease causing organisms. A well should be disinfected following a repair, maintenance or replacement of the pump or if the power has been off for an appreciable period of time possibly causing the pressure tank to loose pressure and the distribution system to back siphon into the well causing possible contamination.
  • Use only a freshly opened bottle of liquid chlorine, as the solution weakens with exposure to air.
  • It is advisable to premix the liquid chlorine into a 5-gallon container prior to pouring the disinfectant into the well.  The recommended dosage for a 50.0PPM chlorine residual is 2-3 cups of 8.25% liquid chlorine for a standard well.
  • Mix thoroughly after adding the chlorine solution. If the well is deep, turn the pump on and off to surge the well.
  • Allow the system to rest overnight for 24 hours.
  • To reduce excess chlorine, pump the well several times then turn on all the outside faucets until the chlorine odor is at an acceptable level.
  • Take a bacteriological sample into a certified private laboratory for analysis. If the test results for total coliform indicate unsafe conditions, then repeat disinfection procedure.
  • Boiling will not treat for suspected chemical inorganic contaminants.

Water Taste and Odors

You may notice that your water tastes or smells earthy, smokey, or burnt. If so, you may need to thoroughly flush your water lines.

If you have any questions regarding this document, please do not hesitate to contact us at
(408) 918–3411.​​​​​​

Fire Recovery and Safety Information

©2024 County of Santa Clara. All rights reserved.