Laboratory Results 

 

Bacteria analyses require 24 HRS of incubation. If the presence of total coliform and or E. coli is detected the laboratory will notify the party listed on the Chain of Custody form as soon as possible. No news is good news! If your sample results are total coliform absent, E. coli absent you will NOT receive a phone call. Expect a formal lab report to be emailed to you within the week. 

 

Interpreting Presence/Absence Results    
 

Total Coliform Absent, E. coli Absent 
A water sample result of total coliform “absent” means it is void of total coliforms and E. coli indicating the drinking water source/system does not contain harmful bacterial contamination. 

Town of Pinedale Microbiology Testing Laboratory DOES NOT declare water “safe” or “potable”. Bacteria testing is used as one water quality indicator, and specific persons and/or regulatory agencies specify indicators for use. 

Realtors and financial institutions: The words on your laboratory report are “Total Coliform Absent”, “E. coli Absent”. The laboratory provides no further official language or interpretation. 

Total Coliform Present, E. coli Absent 
A water sample result of “present” or total coliform positive is reported if coliform bacteria are found in the sample. Generally, coliforms are bacteria that are not harmful and are naturally present in the environment. They are used as an indicator that other, potentially harmful bacteria could be present. The presence of coliform bacteria in tap water suggests that there could be a problem with existing equipment or treatment systems, contamination of the source water, or a breach in the distribution system that could introduce contamination. 

Recommendations: 

1. All public water systems: follow specific EPA repeat and triggered sampling guidelines.

2. Collect a repeat sample to rule out sampling error as the source of contamination and review your sampling procedures to ensure you are sampling properly. 

 

Avoid: Sampling at new faucets or newly repaired faucets, leaky faucets, outdoor faucets or those faucets connected to softeners, hot water heaters, or pressure tanks; setting down the bottle lid or exposing the inside of the lid or bottle to anything other than the sample water (do not rinse or remove powder); and rushing your sample collection.

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Do: Take your time; sanitize the sample tap and your hands; flush the tap for 5 minutes before taking the sample; and minimize the time the sample bottle is opened—open the bottle immediately prior to gathering your sample and replace the lid as soon as the sample is collected. 

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Do:  Thoroughly inspect the water system: Coliform bacteria in a water system are generally either a result of a failure to maintain a “closed” system and/or equipment failure. Visually inspect the system including wells, tanks, chlorinator, etc. Look for areas where soil, leaves, insects, animals, sewage, or animal waste could get into your system. Low water pressure may indicate an underground leak or break or clogged household filter. 

Total Coliform Present, E. coli Present

A water sample result of “present”, or E. coli positive, is reported if E. coli is found in the sample.  E. coli is generally harmful and is present in the intestines of warm-blooded animals. The presence of E. coli bacteria in tap water suggests that there IS a problem with existing treatment systems, contamination of the source water, or a breach in the water system introducing contamination from fecal matter.

Recommendations: 

1. All public water systems notify the EPA immediately and follow specified protocol. 

2. Private well owners: contact a water professional for advice. An E. coli present result should be taken seriously and is cause for further investigation. 

Invalid Results
In rare cases the lab may contact you with invalid results. Any sample that produces an atypical color change (e.g. greenish-black or black) in the absence of a yellow color will be invalidated. According to the manufacturer of COLILERT, water with high iron or manganese levels in the presence of hydrogen sulfide may cause a greenish-black or black color during incubation.  

Repeat samples from the same source are necessary to determine the mineral content of the water and bacteria results.

 
Helpful Resources

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WYDEQ Ground Water Specialists

307-777-9355

www.knowyourwell.org

 

EPA Region 8 (Public Water Systems)

PWS RTCR Rule Manager: Jamie Harris

R8DWU@epa.gov

After Hours Emergencies: 303-312-6327