Drinking Water Lab

NEW Fees for Water Testing

  • Coliform Bacteria - $32
  • Nitrate - $32



Drinking Water Lab Changes
Effective 12/13/2022

If you use the Environmental Health Drinking Water Lab
please review the changes being made.

The water quality lab carries out glass of water 1.jpgbacterial analyses of drinking water, surface water, suspected sewage discharges, treatment plant effluent, marine water, and soils. The lab also performs nitrate analyses of drinking water.

Water Testing

Drinking water may contain contaminants that could pose a human health concern. An important way to assure that drinking water quality is safe for human consumption is to test the water. Testing can help to determine: 1) if a contaminant is present, and 2) if present, whether the level of concentration is high enough for concern.

Pick up and Drop Off Information
(see table below)

  • County Courthouse Building 1, 2000 Lakeridge Dr. SW Olympia
    (360) 867-2631

    DROP OFF ONLY: Mon-Wed 8-5 & Thurs 8-12:30

  • The Atrium, 3000 Pacific Avenue SE, Suite 225, Olympia
    (360) 867-2631

  • Public Health Building, 412 Lilly Rd NE Olympia
    (360) 867-2500

    PICK UP: MON – FRI, 9am to 4pm
    DROP OFF: Mon-Wed, 9am to 1pm. Attach a check for $32.00 - Bacteria or $32.00 - Nitrate

    Sampling Instructions [PDF]

  • Mason Health Department, 415 N 6th Street (downtown Shelton)
    360-427-9670 ext. 400

    PICK-UP: Monday through Friday from 8 am to 4:30 pm
    DROP-OFF: Monday and Tuesday from 8 am to 4:30 pm

    Important Note: You must collect and submit samples to the Mason County Health Department on the same day or else they will exceed allowable holding times prior to being tested by the lab.

    Sampling Instructions [PDF]

  • ​Rainier Town Hall, 102 Rochester St W
    360- 446-2636
    PICK-UP: Monday–Thursday, 8 am–5 pm
    DROP-OFF:  Tuesdays only, 8 am–noon
  • Tenino City Hall, 149 S. Hodgden
    360- 264-2368
    PICK-UP: Tuesday–Friday, 8 am–4 pm
    DROP-OFF:  Tuesdays only, 8 am–noon
  • Rochester (R.O.O.F.), 10140 Highway 12
    360- 273-6375
    PICK-UP: Mon–Fri, 9:30 am–5:30 pm
    DROP-OFF: Tuesdays only, 9:30 am–noon
  • Yelm Public Works, 901 Roton Rd. SE
    360- 458-3244
    PICK-UP: Monday–Friday, 8 am–5 pm
    DROP-OFF: Tuesdays only, 8 am–noon

    Sampling Instructions [PDF]

  • How do I disinfect my well?
    • Follow these directions for disinfecting your well if your water has coliform bacteria in it. This disinfection process treats only biological contaminants, not chemical or mineral contaminants. Disinfecting Your Well 

      1.    Flush the System.

      • If your water is cloudy, let the water run for 10-15 minutes before disinfecting.

      2.    Chlorinate the well.

      • Use household bleach which typically has a chlorine concentration of 6%. Do not use “ultra” concentrated bleach or bleach products with additives or perfumes.
      • The amount of bleach to use is according to the chart on page 2. If you have problems calculating the amount of bleach to use, contact Thurston County Environmental Health.
      • Mix bleach in a bucket of water. Remove well cap, plug, or vent (see diagrams on page 2); using a funnel, pour the bleach into your well.

      3.    Mix the bleach with the well water.

      • Attach a hose to the nearest outside faucet and allow the water to run onto the ground for 1-2 minutes until you smell chlorine. Then place the hose in the hole where you poured the bleach, allow the water to run back into the well for 15-20 minutes.
      • Remove the hose and replace the well cap, plug, or vent.

      4.    Chlorinate the lines.

      • Turn on each tap attached to the well (kitchen, bathroom, outdoor spigot, etc.), starting with the nearest tap to the well, and let the water run until you smell bleach, turn off and then go to the next tap.
      • Turn off electricity to the pump and let sit overnight.

      5.    Flush the chlorinated water out of the system.

      • Choose any outdoor spigot and let the water run onto the ground, away from your septic system (also keep water flow from going into creeks, streams, or where fish or vegetation can be harmed), until you no longer smell bleach. This empties the bleach from the well.
      • Turn on each faucet inside the house until you no longer smell bleach. 

      Once the system has been flushed of all bleach, the water can be used for laundry and bathing but you should not yet use it for drinking, brushing teeth, making ice or preparing food. 

      Wait 3-4 days after flushing the bleach out to collect coliform bacteria samples. You may need to repeat this process several times before coliform test results are “satisfactory”. Also, be aware that the bleach may disturb built-up minerals in your pipes and temporarily discolor your water. This discoloration should disappear once the bleach is flushed out of your system. 

      For more information, call Thurston County Environmental Health Division at (360) 867-2673.

  • My well is making me sick, what should I do?
    • ​Stop drinking the water. Have your water tested for coliform bacteria, see Testing Your Well for more information. Contact our office at 360-867-2631.

  • Who takes care of the public water system that serves my house?
    • ​If you know the name of the water system, you can find that information by searching the DOH Public Water System Database. Or you can call our office at 360-867-2673.

​Lab Location

2000 Lakeridge Drive SW, Olympia
Building 1, 2nd Floor

​Contact Us

  • 360-867-2631
General Drinking Water or Permit Questions
  • 360-867-2673
Public Water Systems

​Social Media

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