PUB2622

Water Protection Program

fact sheet

Division of Environmental Quality

Director: Kyra Moore

Why am I getting this?

The Total Coliform Rule, which has been in effect since 1989, has been updated. The new provisions of the Revised Total Coliform Rule (RTCR) are effective April 1, 2016. The RTCR defines a seasonal water system as “a noncommunity water system that is not operated as a public water system on a year-round basis and starts up and shuts down at the beginning and end of each operating season.” Some examples are state parks, campgrounds and resorts that are open fewer than 12 months each year and depressurize (drain) all or parts of the distribution system during the off-season period. The RTCR requires seasonal systems to complete start-up procedures prior to the start of each operating season and submit certification to the Missouri Department of Natural Resources that the start-up procedures have been completed.

Water system depressurization or any loss of water pressure greatly increases the potential risk of contamination entering the distribution system. Following start-up procedures prior to each season of operation will reduce the likelihood of coliform positive samples that can occur as a result of depressurization. Approved start-up procedures consist of the following elements: basic system assessment, activation of the well and treatment (if any), thorough disinfection and flushing, checking chlorine residuals (if applicable), and collecting special samples.

Our records reflect that your public water system is seasonal, operating fewer than 12 months each year. If this is not correct or if you maintain water pressure throughout the entire distribution system year-round, contact the department’s Public Drinking Water Branch at 573-751-1300 to update its records.

What do I have to do?

Complete start-up procedures before the start of each operating season and submit a certification form to the department. It is recommended that seasonal systems begin start-up procedures at least one month before the start of each operating season.

  • Assess the water system for potential defects and make any necessary repairs
  • Activate or check the source and treatment (if any)
  • Flush all storage and distribution lines until water is clear
  • Disinfect and flush entire system [Optional but recommended for systems that depressurize.]
  • Check disinfectant residual concentrations [Required for systems providing permanent chlorination.]
  • Collect special samples for coliform bacteria and E. coli
  • Complete a Seasonal Public Water System Start-up Procedures Certification Form MO 780-2607
  • Sign, date and submit the form to the department

Preparing Seasonal Water Systems for the Operating Season

A. Assess the water system

  • Inspect water system and area around sources for any potential problems that may increase the possibility of contaminants entering your water system and make the necessary repairs.
  • Please refer to the part of this guidance titled “Seasonal System Start-up Basic System Assessment.” It contains a comprehensive list of questions to help guide you. The questions point at common causes of unsafe water samples historically seen in small water systems but may not apply to your system.
  • The list of questions is for your information only. You do not have to submit it to the department.

B. Activate the source and treatment

  • Turn on the power to the well pumps and any treatment equipment.
  • If the well has a drawdown gauge, measure the static water level and record the result.
  • Flush the wells to waste until the water is clear for several minutes.
  • For activation of treatment equipment, refer to the manufacturer’s operating procedures. If necessary, contact the department’s regional office for assistance. Check where any treatment backwash discharges (water softeners, etc.) to ensure there is no blockage and the water can drain freely. Make sure backwash water can’t re-enter the water supply.
  • Calibrate all instruments used for measuring treatment processes as specified by manufactures’ recommendations, such as chlorine test kits.

C. Flush all storage and distribution system water lines

  • Flush storage and pressure tanks until water lines after storage facilities flow clear for several minutes.
  • Assess the storage facilities during and after flushing for any damage or leaks and replace or repair storage facilities as necessary.
  • Flush the entire distribution system by running water through the entire water system by opening up hydrants, blow-offs, and sample faucets.
  • Close all valves and turn off faucets and then check distribution lines for leaks. The recommended minimum water pressure is 30 pounds per square inch. Water pressure loss indicates there may be leaks in the distribution system and may help you locate leaks.

D. Disinfect the System [Optional]

  • Water systems that do not maintain water pressure in all parts of the water system during the off-season without any permanent chlorination facilities are strongly encouraged to shock chlorinate and then flush all sources, pressure tanks, storage tanks, and distribution lines as an additional step in the start-up procedure.
  • Hand-chlorinate your water system. Refer to the publication Well and Water System Disinfection for Public Drinking Water Systems - PUB2476 for guidance. Do not use chlorine products meant for swimming pools. These products are not intended for disinfecting wells and contain additives you do not want in your well.
  • If anyone could drink the water during the chlorination process, use a 2 ppm chlorine residual, using ¾ cup of unscented household bleach for every 1,000 gallons of water in the system.
  • If no one has access to the water, use a 5 ppm chlorine residual, using 1½ cups of unscented household bleach for every 1,000 gallons of water in the system. More details are available in “Well and Water System Disinfection for Public Drinking Water Systems.”
  • Begin closest to the well and working outwards to the ends of the distribution lines, turn on sample taps and hydrants to draw chlorinated water through the entire water system. Leave taps on until chlorine odor is detected by smell or residual is detected with a chlorine test kit.
  • Turn off all taps and hydrants and leave water with detectable chlorine residual in the distribution lines overnight (at least 12 hours) to allow time for adequate disinfection.
  • Flush the disinfectant from the system by opening taps and hydrants until water is flowing clear and no odor of chlorine or residual detected with a chlorine test kit.

WARNING: When flushing, water containing detectable amounts of chlorine should not be discharged into storm drains or any surface water body such as tributaries, lakes, streams, or ponds as it may kill fish and aquatic life sensitive to very low levels of chlorine. Contact the department’s regional office for guidance and a copy of Discharging Chlorinated Water Best Management Practices.

E. Check disinfectant residual concentrations. [Required for chlorinating systems]

  • Water systems providing permanent chlorination must have a chlorine test kit.
  • Check with the department to determine if the chlorine testing device being used is acceptable. If you do not have a chlorine test kit, contact the department for assistance on how to obtain one.
  • Check to make sure you have enough reagent packets to test free and total chlorine residuals.
  • Purchase fresh chlorine (unscented household bleach) and mix fresh feed solution. Clean or replace all lines, injectors, and other parts as necessary. Verify the feed rate of the feed pump.
  • Measure the chlorine residual from taps or hydrants throughout your distribution lines.
  • Untreated systems must not have any detectable chlorine residual when coliform samples are collected. If chlorine is detected, flush the water system until chlorine is no longer present.
  • Chlorinated systems must have a free chlorine residual greater than 0.5 mg/L entering the system and a total chlorine residual greater than 0.2 mg/L throughout the distribution system at the time and location of each bacteriological sample.

F. Collect special samples for bacteriological analysis

  • Collect at least one special coliform sample from your distribution system. Systems with multiple distribution systems or distribution lines should collect a special sample representing each segment to ensure the entire system is free of coliform bacteria prior to each season.
  • Systems that routinely collect more than one sample per month should collect at least the same number of samples as part of their start-up procedure.
  • Collect samples at least two to three weeks prior to opening to allow for sample results and additional actions if needed.
  • Refer to "Sample Collection Techniques for Coliform Analysis,” available at dnr.mo.gov/env/wpp/monitoring.htm for instructions.
  • For “Sample Type” on the environmental sample collection form, mark “Special.” This type of sample will not count for compliance, and is strictly intended to check if disinfection and start-up procedures have been successful.
  • Re-evaluate the water system if any samples are total coliform positive (unsatisfactory).
  • The Department of Natural Resources does not recommend serving water to the public until special samples are absent of total coliform.
  • If positive samples persist, contact the department’s regional office or Public Drinking Water Branch for additional assistance.
  • To order bacteriological sample bottles, call the Public Drinking Water Branch or complete a bottle order request.
  • Please note that public water systems that use a certified laboratory other than the Missouri Department of Health and Senior Services – State Public Health Laboratory must submit all special sample results for coliform bacteria to the department’s Public Drinking Water Branch.

G. Complete “Seasonal Public Water System Start-Up Certification”

  • Fill out the Public Water Supply Information for your public water system.
  • Provide the approximate “Start Date” and “End Date” for your public water system anticipated for this coming season of operation. (The month you plan to start and finish is adequate here.) If your system is not seasonal and you plan to begin monitoring monthly all 12 months of the year, please indicate by entering 1/1 – 12/31 in the Start Date and End Date respectively.
  • Provide an answer to Question 1 under the Public Water System Operation Question section regarding depressurization.
  • Check all Seasonal Start-Up Procedures completed prior to the operating season provided above under the Seasonal System Start-Up Procedures section.
  • Sign and date the Certification Form attesting to the completion of the start-up procedures.

H. Submit completed “Seasonal Public Water System Start-Up Certification Form”

  • Submit the completed “Seasonal Public Water System Start-Up Certification Form” to the Missouri Department of Natural Resources, Public Drinking Water Branch, at the address listed below, before the start of the operating season using any of the following options:
  • Keep a copy of completed form in your files. Copies must be kept on file for at least five years.
  • Failing to complete start-up procedures or failure to submit the certification is a violation of the RTCR requiring public notification.

For more information regarding the Revised Total Coliform Rule requirements, contact the Department of Natural Resources Public Drinking Water Branch.

Other Useful Links

Seasonal System Start-up Basic System Assessment

Reviewing the list of questions below as a part of the seasonal start-up procedures will help you to assess your system and identify potential problems with your water system that may allow contamination to enter, or may cause operational problems in the future. If you find a possible defect, make the necessary improvement and if you are unsure what improvement to make, contact your Department of Natural Resources regional office for assistance. Not all items listed below will apply to all water systems. For example: not all seasonal water systems disinfect, some water systems have gravity storage, while others use pressure tanks.

Well and Well house

  • Is the well and well house protected from tampering?
  • Is the well casing (wellhead above ground you can see) structurally sound?
  • Is the well cap free of openings that would allow an insect to crawl into the well?
  • Is the sanitary seal tightened securely with no openings?
  • Is the well casing vent, inverted, above the well head and intact? (Recommended 1½ -diameter vent)
  • Does the casing vent have an 18-mesh screen or finer and intact to keep insects out?
  • Is there a functioning raw water sample tap for samples direct from the well?
  • Is the well house free of stored volatile chemicals such as pesticides, gasoline, herbicides, paints and solvents?
  • Is the well house clean and free of insects and rodents? (Look for droppings, chewed papers, or nesting materials.)

Chlorination (for water systems that have full time disinfection)

  • Did you check the chemical injection point and clean it? (Following manufacturer’s recommendations)
  • Did you check the chemical foot valve and clean it? (Following manufacturer’s recommendations)
  • Did you check chlorine tubing and replace any hardened or old tubing?
  • Is the chlorine residual test kit working and are the reagents fresh? (If reagent is past the expiration date, discard and order an adequate amount of new reagent)
  • Do you have a fresh supply of chlorine solution (bleach)? (The bleach decomposes over time whether or not the container has been opened. If the solution is over a year old, discard and purchase new bleach)
  • Is the chemical feed pump working properly and pumping an adequate dose throughout the distribution system?
  • Test free chlorine residual on at least two separate days to determine if there is a chlorine demand. Evaluate results and make adjustments as needed.
  • If required to disinfect: Do you have enough chlorination report forms for this season?
  • If not required to disinfect: Will you use chlorination report forms or keep a log book?
  • Have you calibrated all instruments used for measuring treatment processes as specified by manufactures recommendations, such as chlorine test kits?

Storage Tanks, Standpipes and Towers

  • Did you disinfect and flush storage tank?
  • Was the inside of the tank cleaned within the last five years? DATE:__________________
  • Does the overflow pipe have flapper valve, or screened and screen intact?
  • Does the overflow drain to a splash-pad?
  • Is the access hatch locked?
  • Is the tank vent properly screened and is the screen fully intact?
  • Are insects and spiders being kept out of the tank? (Check the inside of the lid)
  • Is the bottom of the tank free from sediment buildup?
  • Are the storage tank roof and sides structurally intact without holes and cracks?
  • Are the water level controls functioning properly?

Distribution Lines

  • When you walk the lines, can you ensure none of them are exposed?
  • Have you checked your system for leaks?
  • Have you flushed all distribution lines?
  • Do you have good chlorine residual at end of distribution? (For systems that disinfect)

Sample Sites

  • Are all routine and repeat sample taps working properly?

After assessing your public water system using the checklist above and after completing each applicable start-up procedure listed on the “Seasonal Public Water System Start-Up Procedures Certification Form”, check the appropriate boxes and submit a copy of your completed “Seasonal Public Water System Start-up Procedures Certification Form” to the department’s Public Drinking Water Branch no later than 10 business days before opening to the public. Please submit completed form to the department and keep a copy of the completed certification form for each season for your records. Copies must be kept on file for at least five years.


Nothing in this document may be used to implement any enforcement action or levy any penalty unless promulgated by rule under chapter 536 or authorized by statute.


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