Total Coliforms & E coli in Drinking Water Samples

 


Ingestion of pathogens in drinking water may result in gastroenteritis, hepatitis, myocarditis, paralysis, acute hemorrhagic conjunctivitis, meningitis, and/or other negative health impacts.

The presence of either of the pathogenic-indicating organisms otal coliforms or generic E. coli demands that an investigation promptly ensues to determine how the contamination occurred, followed by action taken to correct the fault in the water system, followed by resampling to verify the action taken has been effective.

We are here to help with sample collection, analysis, and result interpretation.


Testing Water for Compliance Purposes

Public Water Systems

Murray-Brown Laboratories maintains certification by the State of Colorado Department of Public Health and Environment (CDPHE) to analyze public drinking water compliance samples for total coliforms & E. coli by the Colilert Method (SM 9223) which are collected and submitted by Public Water Systems (PWS) in their efforts to satisfy the requirements of the Total Coliform Rule (TCR) under the Safe Drinking Water Act (SDWA).

The purpose of the TCR is to monitor for the presence of microbes, specifically coliform bacteria, and to determine whether the drinking water in the distribution system of a PWS is potentially contaminated with pathogens.

Faucet Selection

The purpose is to test the water distribution system NOT the plumbing of an individual building.

Therefore, all precautions should be taken to eliminate collecting a sample which may yield a positive result due to the potential for contamination some faucets have (see FAQ 2).

Testing Water for Non Compliance Purposes

Manufacturers of Goods or Home Owners

In the world of food preparation, water isn’t just for drinking.  It’s added to recipes, sprayed on facility equipment, and used to wash employee hands.  The water from your pipes will touch nearly every surface in your production room – which means it needs to be as clean and safe as possible.

Because of this manufacturers of goods should perform regular tests on the water in their facility to check for the presence (or more desirably, the absence) of total coliforms and E. coli in their facility’s water source in order to assess the quality of water coming into contact with foods and/or goods produced.

Home owners or others may also desire to assess the quality of their water which may come into contact with humans in various ways.

Faucet Selection

Samples being collected from a production facility or home to assess water which may be directly consumed by humans, or come into contact with goods destined for human consumption, must be collected from a representative tap which supplies such water, no matter its condition.

MBL’s technicians are trained in collecting drinking water samples.

We are also available 365 days a year to accept compliance samples from PWS.

Contact us for off hour receipt, including weekends and holidays.

Drinking Water Testing FAQs

Drinking Water Testing FAQs

1. Can I & How do I collect by own Drinking Water sample?

If you desire, you may collect your own drinking water sample; we can supply all the materials are instructions for doing so.

Obtain a Drinking Water Sample Collection Kit from Murray-Brown Laboratories containing:

Record the following information in your on-site sample log book and on the MBL Drinking Water Sample Submission Form:

  • Name of system (PWS site identification number, if available)
  • Unique Sample Identification (if any, as indicated on the PWS Monitoring Plan, i.e. “Bathroom Sink”)
  • Sample Site Location (including physical address)
  • Sample type (i.e. Routine Compliance, Repeat Compliance, or Special Purpose Non-Compliance)
  • Date and time of collection
  • Analysis requested
  • Disinfectant residual, if applicable (samples for compliance purposes)
  • Name of sampler
  • Any remarks

Following the Sample Collection Instructions, aseptically collect and transport the sample.

 

2. How do I select the site & faucet to collect my Drinking Water Sample? What is a Low Contamination Risk Faucet?

Selecting what faucet, including its type, location, and the water source which feeds it, to collect a water sample from depends upon why the sample is being collected.

  • If the sample is being collected for compliance purposes under the Total Coliform Rule, then the purpose is to test the water distribution system NOT the plumbing of an individual building.  Therefore, all precautions should be taken to eliminate collecting a sample which may yield a positive result due to the potential for contamination some sampling sites have by selecting a Low Contamination Risk Faucet (see blue box below).
  • If, however, the sample is being collected for non-compliance purposes from a production facility or home to assess water which may be directly consumed by humans, or come into contact with goods destined for human consumption, then the sample must be collected from a representative tap which supplies such water, no matter its condition.  If such testing does reveal the presence of coliforms and/or E. coli, it would be appropriate to conduct an investigation to determine the cause, develop, and implement appropriate corrective action, and follow up with repeat samples to confirm the success or failure of the corrective action taken.

Faucet Selection for Samples Collected for Compliance Purposes

The TCR requires each small community drinking water system to sample for coliforms according to a written plan, (PWS Monitoring Plan) which must be made available to the CDPHE.  Having a written sample collection protocol helps ensure that all sampling is done correctly, even when assignments of water system personnel change.

The plan specifies where in the distribution system routine samples will be drawn in order to ensure that they are “representative” of the water supplied to every customer.  Representative samples that accurately reflect the quality of the finished water are crucial because, if coliforms are in the water supply, they may not be found uniformly throughout the distribution system.  The sampling plan also designates repeat sampling sites to be used if a sample drawn from a routine sampling point tests positive for coliforms.  The purpose of sampling is not to draw “clean” samples, but to identify any coliform contamination so it can be dealt with promptly.  Because of this, it is important to identify dead ends and trouble spots in the distribution system for sampling locations.

When defining the Plan, sampling site locations, including specific faucets, which, according to their location or condition, have a high potential for contamination should be avoided as they may result in a positive result that is not truly representative of the water quality in the distribution system:

Low Contamination Risk Faucet

Water taps used for sampling should be free of aerators, strainers, hose attachments, mixing type faucets, purification devices, and should be in good repair (no leaks).  Avoid collecting samples from kitchen or utility sinks with swing arm necks, or from swivel-type faucets that have a single valve for hot and cold water.   It is not a good idea to collect water samples from:  new plumbing & fixtures or those repaired recently; outside taps or hoses, faucets that have leaky packing material around the stem; faucets that supply areas, such as janitorial or commercial sinks, where bacterial contamination is likely; faucets close to or below ground level; faucets that point upward; faucets that have treads on the inside of their spouts; faucets connected to cisterns, softeners, pumps or pressure tanks.

References:

CDPHE TCR Best Sampling Practices — Drinking Water Sample Collection Techniques.

  Open PDF

EPA Developing a Sample Siting Plan — How to develop a Sampling Monitoring Plan and how to determine sampling sites.

  Open PDF

EPA Sample Collection Techniques — An overview of drinking water sample collection with images.

  Open PDF

EPA Ground Water Rule Sample Collection & Transport:  A Quick Reference Guide — An overview of ground source water collection; page 2 details shipping instructions for samples.

  Open PDF

EPA Quick Guide to Drinking Water Sample Collection — General Sampling Procedures; Proceed to Total Coliform Rule.

  Open Link

 

 

3. Will MBL collect my drinking water sample for me?

MBL is qualified to collecting drinking water samples for both compliance and non-compliance purposes which are to be analyzed for total coliforms and E. coli.

Upon request and by appointment, MBL can collect drinking water samples if you so desire.

If you are a Public Water System, you must provide the exact sample location according to your Monitoring Plan, including the Site Name and Site Address.

Please contact us to discuss the price and availability of this service.

4. How do I determine the Chlorine Residual of my water prior to collecting a sample?

Sample Collection Requirements From EPA Manual for the Certification of Laboratories Analyzing Drinking Water:

  • Public water systems need to measure residual disinfectant concentrations with an EPA approved method.

EPA Analytical Methods Approved for Drinking Water Compliance Monitoring under the Disinfection Byproducts Rules — Proceed to Combined, Free, or Total Chlorine.

  Open PDF

HACH EPA Compliant Methods

  Open Link

5. How do I investigate a total coliform positive result in my drinking water sample?

Below are links to various investigational resources you may use to aid in determining the root cause for a total coliform positive in a drinking water sample.

EPA Distribution System–>Water Quality and the Distribution System (see resources at bottom of page).

  Open Link

EPA Small Systems Guide to the Total Coliform Rule

  Open PDF

CDPHE Total Coliform Rule Compliance

  Open PDF

CDPHE Drinking Water Certificate

MBL CDPHE Water Cert 2015


FREQUENTLY ASKED QUESTIONS


General Sample Submission FAQs

General Sample Submission FAQs

How do I get my results?
MBL delivers results via E mail in the form of a PDF Certificate of Analysis to the recipients designated in the Laboratory Deliverables section of the New Customer Package.
MBL will only report to a third-party at the consent of Customer.
Upon request, results may also be delivered via fax or USPS mail, if this is your preferred method of delivery.
For multiple recipients of results, we recommend establishing an internal distribution list whereby you can define and maintain such recipients (i.e. labresults@yourcompany.com).
How long do you keep my sample & can I have them back?
Sample Retention Times (after reporting results) are as listed in the table below.
Any repeat, additional, and/or confirmation analysis must be requested by the Customer within the retention time frame.
Repeat analysis performed at the Customers' request will be charged to the Customer if the original results are confirmed.
To limit liability, samples submitted to MBL will not be returned to Customer because they have been stored in a facility which is known to have live pathogens.

Sample Retention Times (After Reporting Results) are as Follows:


Sample Type Retention Time
Qualitative Microbiology Negative Enrichments / Samples – Not Retained
Positive Enrichments / Samples – 24 Hours
Quantitative Microbiology 2 Business Days
Chemistry Analyses 2 Business Days
Other Analyses 2 Business Days 

How long does it take to get results?

Specific turnaround times for each test can be found in our Test Library.

Our turnaround times are approximate, and do not include weekends or holidays for chemical and some microbiology analyses.

We will always try to begin analysis on the day we receive your samples.  However, samples submitted after 3pm may be held until the next day.

A 50% surcharge will be assessed for samples submitted after 3 pm requiring same day set up for microbiological analysis.

E. coli O157:H7 results are typically reported by 6:00am Tuesday through Friday, 7:00am on Saturday, 2:00pm on Sunday, and 10:00am on holidays.

Alternative terms regarding turnaround times may be arranged on a case-by-case basis.

What is the Sample Description?

This is assigned by You, the Customer, to identify the name of samples submitted to MBL, as indicated on the Sample Submission Form.

You should describe your sample in a way which makes sense to you and is meaningful now and later when referring to your records.

Describing samples in a like and similar manner each time you submit the same type of sample can help you later in comparing data from one lot to another.

General Methodology FAQs

Methodology FAQs

How much sample do you need for a test?

Typically, larger sample sizes equate to more representative results.

In general, most analyses require 100 grams to 500 grams of your product for an accurate test.

Each analysis is different, so please visit our Test Library for specific sample size requirements.

What Certifications do you maintain and where can I download them?

We maintain two Certifications (click on the image to download).

Please see our Accreditations Page for more information on our Certifications and our Commitment to Quality.

ISO/IEC 17025:2005 Certificate

Murray-Brown Laboratories ISO 17025 Certificate Exp 08-31-18

CDPHE Drinking Water Certificate

MBL State of Colorado Drinking Water Certificate 010117 to 123117

What matrices can you analyze?

We can handle a variety of matrices, including nearly all foods and food products, environmental samples, and dietary supplements.  Please inform us if you have any matrix concerns.

What methods will you use to analyze my sample?

Murray-Brown Labs’ ISO/IEC 17025:2005 Certificate itemizes all analyses/methods for which we are accredited.

Unless specified by the Customer in writing, we will select the method believed to be the most appropriate for analyzing samples based upon the information you provided.

We will notify you when a method you specify is believed to be inappropriate or out of date, and reserve the right to decline the use of such a method.

Cost & Payment FAQs

Cost & Payment FAQs

What are your Payment Terms and what forms of payment do you accept?

Payment Terms and Conditions

Samples are as submitted by Customer; MBL will not invoice a third party unless agreed upon by MBL, at MBLs’ sole discretion.
Customer must have a valid credit card on file with MBL; this card will be charged immediately upon completion of analyses (per project or weekly invoice as dictated by MBL), unless credit terms have been granted.  Customers scheduling $500 or more per week in MBL tests and services must apply for credit terms to pay by check or be must be approved by MBL to pay via credit card on file.
MBL may extend credit to Customer based upon the findings of a credit or other reference check, and/or the history with Customer and/or its representatives.  Customer granted credit agrees: payment terms are Net 15 days; MBL will charge credit card on file for overdue balances; a late charge of 1.5% per month will be added to all unpaid balances; all current and/or ongoing work will be halted for accounts overdue by 30 days and no additional work will be accepted until the balance is paid in full; accounts delinquent 90 days will be scheduled for collections; Customer is responsible for collection and/or legal fees MBL incurs as a result of securing payments for invoices which are in default.
MBL reserves the right to collect prepayment from Customer; costs of analyses are as defined via our Pricelist and/or Quotations.  Additional charges, as assessed by MBL and agreed upon by Customer, may be applied for: sample preparation; rush and/or weekend analyses; sample collection and/or pick-up; consulting; time required to complete above and beyond Customer requests.

All Major Credit Cards Accepted

Credit Cards

What are your prices? Are there discounts for volume samples?

Please contact us for pricing including large volume discounts.

Sample Collection & Transportation FAQs

Sample Collection & Transportation FAQs

Do you offer sample pick up and how much does it cost?

Yes – Below you can find our sample pick up pricing, schedule, and fees.

Sample Pick Up is Free if:

 

 

 

Otherwise, Pick Up Fees are:

  Cost of testing is greater than or equal to $100; 24 hours notice is given;

  Pick up location is within 20 miles of MBL;

  Wait time for samples upon arriving at facility is less than 5 minutes.

 

$25 per pick up

(within 20 mile radius; plus $1 per mile over 20 miles; plus $1 per minute past 5 minute wait; plus $25 if less than $100)

When the Customer employs MBL to courier samples, MBL agree to do so in a manner which preserves the integrity of the sample(s).

Do you perform on-site sample collection?

Yes – Our trained staff is available to perform sampling at your or a third-party site.

Please contact us to discuss the price and availability of this service.

Sample collection by MBL on behalf of the Customer will take place according to an appropriate Sampling Plan, selected and/or designed by MBL, which will be available to the Customer for reference.  MBL is not responsible for alterations made by the Customer to the larger portion from which MBL collected samples after such sample collection occurred; such alterations may invalidate reported results.

When the Customer employs MBL to collect and/or courier samples, MBL agree to do so in a manner which preserves the integrity of the sample(s) and the larger portion from which it was collected.

We can also, if needed, assist in training your staff in proper sample collection techniques and procedures.

How do I collect a representative sample?

There is no short answer to this question and it is best to discuss this with any regulatory body that you are dealing with and any associated regulatory program by which your are governed.

We can provide guidance and assistance with most of the common regulatory requirements and associated sampling protocols.

MBL will provide a result which is representative of the sample submitted; it is the responsibility of the Customer to ensure that the sample submitted is representative of the larger portion from which it was collected.

How do I ship my sample to the laboratory?

Usually via overnight courier if refrigerated or frozen with enough coolant to maintain the proper temperature until receipt at our laboratory.

If you are uncertain about the details, please call us to discuss them.

How should I handle my sample before submitting it to the laboratory?

The integrity and representativeness of each sample must be maintained through delivery to the laboratory.

What type of container should I collect my sample in?

The appropriate container for each type of sample is included in our list of tests.  Please call to discuss any non-typical situations.