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Well Use in Droughts

General information

Our goal, especially during the current drought, is to work with you to maintain an adequate and safe water supply for your household. If your well or spring is not producing enough water for your needs, please review the information in these frequently asked questions as we continue to seek resources and options for homeowners using wells for water supply in rural San Mateo County.

1. My well is not producing enough water for my home, what should I do?

  • You should start working now to secure a sustainable water source for your home … deepen your well, drill a new, deeper well, or connect to a public water system if possible. 
  • If you have a holding tank, you can contract for potable water delivery (see below for water haulers and requirements/suggestions). Hauling water to your home is a short-term solution to a long-term problem Make sure you are only using your water for the bare necessities—drinking, bathing, etc., and not for landscape irrigation.
  • Make sure you have low-flow fixtures installed, and there are no leaks, drips or running toilets in your home that may be wasting water.
  • Additional tips may be found here and here.

2. Where can I find a licensed potable water hauler?

Potable water haulers are licensed by the California Department of Public Health. A current list of licensed potable water haulers sorted by county is available here. There are currently only two licensed haulers listed for San Mateo County, so check surrounding counties too.

3. Do I have to use a licensed potable water hauler?

While unlicensed companies may deliver water to you, we strongly urge you to use a licensed potable water hauler because only licensed haulers have to meet rigorous quality standards.  Without knowing the quality of the water delivered, you may put you and your family at risk for contracting water-borne disease/illness.

4. Are there any precautions to take if I use hauled water?

There are inherent risks of contaminating hauled water during transfer and storage.  It is recommended that, to the extent possible, water in your storage tank maintains a detectable chlorine level of 1 part per million.  Even with this precaution, it is not advisable to use hauled water for drinking or food preparation, including washing produce. If you have to use hauled water, please contact Environmental Health staff for more information on precautions to take, including disinfection protocols.

5. I don’t have a water holding tank … where can I find one?

​Your local plumber is a great resource for obtaining and installing a water holding tank. Nearby suppliers include, but are not limited to:

  • Scotts Valley Sprinkler Co
    5010 Scotts Valley Dr.
    Scotts Valley, CA 95066
    (831) 438-6450
    Brands of water storage tanks: Poly Processing, Norwesco, Bushman
  • Make A Buck Co.
    3391 Cabrillo Ave
    Santa Clara, CA 95051
    (408) 246-7932
    (800) 400-7932
    Type of water storage tanks: Plastic tanks

​You can also check your local yellow pages.

6. Do I need to get a permit to install a holding tank at my home?

It depends on the area of the county and size and configuration of your desired holding tank. Contact the San Mateo County Planning and Building Department at (650) 599-7310 or (650) 599-7311. No separate Environmental Health permit is required. Once the tank has been installed, Environmental Health is available to assist with any disinfection protocols.

7. If I need to drill a new well for my home, what permits will I need before beginning?

Prior to obtaining a drilling permit from Environmental Health, you may first need to work with the Planning and Building Department to determine if you need a Coastal Development Permit (CDP) or Coastal Development Exemption (CDX). Once you have received approval from the Planning and Building Department or determine that no CDP or CDX is needed, you’ll need a drilling permit from Environmental Health. You can download the well drilling application here. Please note that if a CDP or CDX is needed, Environmental Health may work with the Planning and Building Department to request an emergency CDP or CDX to expedite the well permitting process. 

8. What resources are available to homeowners?

Environmental Health staff are available to assist you. Please contact them at (650) 372-6200 or While there currently is no state or local drought relief funding available for individual well owners, we are lobbying the state to make funds available for affected water users. This is one more reason to let us know of any problems you may have—to inform our lobbying efforts. You can find additional state resources here.

9. How do I disinfect a well after a storm?

  • Introduce one cup of household bleach into the well through opening at the slab top or casing. Newer wells should have a capped gravel pack pipe or disinfection pipe at the slab which can be opened. For wells deeper than 50 feet, introduce two cups of household bleach into the well.
  • Add five gallons of water chlorinated with ½ cup of household bleach to the well to force the solution out into the surrounding formation.
  • Operate the well pump until a distinct odor of chlorine can be detected in the water after the pressure tank or somewhere at the house.
  • If the well was operational during the storm, and there is a risk that house lines are contaminated, run the water until the smell of chlorine can be detected at the kitchen and bathroom sinks.
  • Allow the chlorine solution to remain in the well and water lines for at least four hours, preferably overnight.
  • After disinfection, pump the well and run the water in the house until the odor of chlorine is no longer detected.
  • To collect a sample to be tested for bacteria, it is best to use a container provided by the laboratory. If one is not available, use a 12 oz. or greater glass jar which has been sterilized by boiling (lid included). If possible, take the sample directly from the well or an outside tap. Run the water for one minute, take sample being careful not to touch the inside of the lid or jar. Transport to a commercial laboratory or the County Public Health Lab. The sample should be on ice and arrive at the lab no more than 5 hours after sample collection for valid results. Test for “Coliform Bacteria, presence/absence.” Call the laboratory first to ensure they can do the required analysis. The County Public Health Lab is located 225 W. 37th Avenue, Room No. 113, San Mateo, CA 94403 | (650) 573-2500.