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 City of Round Rock Environmental Services Laboratory
Testing Services

Bacteriological Water and Waste Water Testing

The Environmental Services Laboratory offers Bacteriological Water Testing to water utilities, construction and other private businesses, laboratories and private well and home owners.

Bacteriological water testing is used for the detection and identification of

  • Total Coliform in Water
  • E.coli in Water and Waste Water

Sample Containers
Samples must be submitted using laboratory-issued, sterile collection bottles.  Bottles are available at the Environmental Services Laboratory Monday through Thursday from 8 a.m. to 4 p.m.

Sample Collection
Proper sample collection is the responsibility of the submitter.  The Environmental Services Laboratory has developed Standard Operating Procedure #01-28-09, Bac-T Sample Collection, Transportation, and Storage for External Customers.  You are encouraged to review this document in its entirety (click to download document).  The basic steps are outlined below:

Sample Site Preparation for Drinking Water Samples

 1.  Select a faucet that will be a representative sample of the main water source.
 2.Remove any aerator, strainer or any other device that would restrict the free flow of water from the tap selected.
 3.  Allow water to run 2 to 3 minutes.
 4.  Turn water off, if possible, and disinfect the tap with bleach or alcohol.
 5.Turn on and adjust the water flow to a slow and steady stream to permit filling the container without splashing.

Sample Collection

Unscrew the bottle cap carefully and hold it in one hand while filling the bottle.  Do not touch the inside of the cap with your hand.
Fill the bottle slightly above the 100 ml line etched on the container.  Samples that do not contain the minimum 100-ml volume cannot be accepted.
 8.  Replace cap carefully and close tightly to avoid leakage.
 9.  Turn off tap.

Some DON'Ts to ensure proper collection
-  Don't rinse out the container
-  Don't touch the inside of the container or cap
-  Don't allow the container to touch the water tap
-  Don't fill the container to overflowing

Sample Storage
It is recommended to refrigerate the sample if it is not immediately submitted to the Environmental Services Laboratory.  Do not freeze the water sample.

Sample Hold Times
Drinking water samples must be received within thirty (30) hours of collection.  Wastewater, pool/spa, and river/lake and rainwater samples must be received within six (6) hours of collection.

Sample Transport
It is recommended to place the sample in a cooler or Ziploc bag with loose ice or an ice pack to keep it cool during transport.

Chain-of-Custody Forms
Chain-of-custody forms are available at the Environmental Services Laboratory.

Test Results
Test results are available on the day following sample submission.  A preliminary report by facsimile or e-mail will be provided upon request.

Reporting Responsibilities

 Sample Source

 Sample Types


Drinking water from Public Water System

Distribution, Repeat and Raw

Laboratory will report positive results to TCEQ within 24 hours
Drinking water from Public Water System

 All sample types

Laboratory will report all results to TCEQ by the tenth (10th) day of the following month
Private Well Water Submitter is responsible
Wastewater Submitter is responsible
Ambient Water (pool/spa, lake/river, rain) Submitter is responsible
Ice Machines, Bottled Water Vendors  Submitter is responsible


Calibration Verification of Field Chlorine Instruments

The calibration verification test is designed to fulfill the requirement of Texas Administrative Code (TAC) 290.46(s)(2)(c)(i), whereas the accuracy of manual disinfection residual analyzers shall be verified at least once every thirty (30) days using a chlorine solution of known concentration.  (Click here to link to the Texas Administrative Code.)

Please contact the laboratory for testing times.



For more information, please contact:
City of Round Rock Environmental Services Laboratory
Phone: (512) 218-5561
Fax: (512) 341-3316
E-mail:  Water_Lab_Question

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City of Round Rock | 221 East Main Street, Round Rock, Texas 78664 | Phone: (512) 218-5400
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