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Public Health Regional Laboratory: Testing Services

Bacteriological Water Testing

This testing service is available to the general public, water agencies, shellfish growers, and environmental health inspectors in Sonoma, Mendocino, and Lake counties.

Testing Method

Bacteriological Water Testing is used for detection and identification of:

• Coliform bacteria
• Fecal coliform
• E. coli

Specimens

Bacteriological Water Testing is FDA approved for water samples. Samples must be submitted using laboratory-issued collection bottle. Collection bottles are available free of charge during normal laboratory hours.

Specimen Collection

For collecting water samples from private sources:

Sample Collection Preparation

1. Select a faucet from the cold water supply that will represent a sample of the main water source. Do not use the hot water supply.
2. Remove any aerator, strainer, or any other device that would restrict the free flow of water from the tap selected.
3. Adjust the water to provide a smooth flow and allow it to run to waste for 2 or 3 minutes.
4. Immediately prior to drawing the water sample, restrict the flow to permit filling of the container without splashing.

Collecting the Sample

5. Unscrew the cap carefully. Do not lay cap down, but hold in one hand while filling container. Do not touch inside of cap with your hand.
6. Place the container under water flow allowing the container to fill to the 100 ml line marked on the container.
7. Replace screw cap tightly. Shake or invert 10 to 15 times. Turn off the tap.

Some don'ts to insure proper collection:

• Don't touch the inside of the sample container.
• Don't allow container to touch water tap.
• Don't rinse out the container.
• Don't wipe the container.
• Don't breathe into the container.
• Don't fill the container to overflowing.

Collect the sample the same day you plan to bring it to the lab.

Specimen Storage

If unable to submit the sample within 1 hour of collection, refrigerate the sample.

Specimen Transport

When transporting a sample to the lab, use an ice pack and keep out of direct sunlight. Drinking water samples more than 30 hours old are not acceptable for testing. Wastewater, river, and lake water samples must be received within 5 hours of collection.

Testing Results

Results are available within 2 to 3 normal working days after receipt of specimen at the laboratory. A written report will be provided for all specimens received. Positive results will be phoned and/or faxed upon request.

Specimen Submission Forms

Use the Bacteriological Examination of Water - Blue Slip for general testing, and the Grey Slip for water systems reporting to agencies.

Cost

Please call for current pricing.