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Startup Tips for Seasonal Systems

Make your start up trouble-free by ensuring your system is clear of coliform bacteria before you begin serving water to the public.
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Not only is a seasonal start-up procedure a good idea, but new coliform rules that went into effect April 1, 2016 require all seasonal systems to complete startup procedures and return a signed checklist (pdf) to Oregon DWS before serving water to the public each season. [See certain exemptions from the start-up procedure in our Pipeline newsletter.]Failure to complete, sign and return the checklist to DWS before opening will result in a violation and require posting of public notice at the water system.
Check your water system's "Operating Period" on Drinking Water's Data Online website. Year-round systems will show an operating period of Jan. 1 - Dec. 31. If only certain months are shown, it is considered a seasonal system. This may be an important distinction if part of your water system is shut down but another part remains open to the public year-round (thus the system itself is not seasonal).

Preparations should begin at least one month before you plan to serve water to customers. You will need time to evaluate the condition of your water system, make repairs, disinfect, and collect samples to make sure the water system is free of coliform bacteria. Follow the steps below. If you don't already have one, consider obtaining a test kit for measuring "free chlorine" to check chlorine levels, although most will not measure the high concentrations needed for short-term full disinfection methods. Note: These steps do not address all aspects of reactivating treatment at seasonal surface water systems.

Inspect the system. Install all components that may have been removed for winterization. Inspect all components of your water system for winter damage, including your distribution lines, valves, and other fixtures. Review the Operations & Maintenance Manual and Emergency Response Plan. If you identify any deficiencies, make the necessary repairs.

Winter erosion damage at springbox

For example, check to see that the well's sanitary seal is intact at the cap, as well as the screen on the vent. For springs, clear away dead and downed vegetation to eliminate cover for small animals, and check that the spring box lid is watertight and locked. Make sure the diversion ditch is clear of debris and directs surface water around the spring collection area. Check water storage tanks for damage to floats, valves, screens and wires (see Safety Precautions on the Disinfection page). Fix any tank leaks or other openings that might allow small animals such as mice or birds to come in contact with the stored water.

Activate the source(s). Make sure all drain valves are closed. Open or close main valves as shown in your system's Operations Manual. Even if a valve is already in the correct position for activation, this is a good time to "exercise" the valve by turning it back and forth through its full range. Finally, turn on the power to your source pump(s), or open the valve from the spring box.

Activate the treatment system (if applicable). Perform annual maintenance on pumps and components as recommended in your operations and maintenance manual. Turn on the power to the treatment equipment. For a chlorinated system, purchase fresh chlorine, mix fresh feed solution, replace or clean all lines and parts, and verify the feed rate of the feed pump. For other treatment, refer to the manufacturer and your operating procedures.

"Open" the system and initial flush. Run water through the entire water system by opening hydrants, blow-offs, and faucets until flow is clear. Make sure pressure tanks are pressurized.

Disinfect. Disinfect and flush all sources, pressure tanks, storage tanks, and distribution lines. Leave chlorinated water in the system components and distribution lines for at least 24 hours. See System Disinfection Details.
Take care when flushing the chlorine from the lines and tank. Chlorine at this level will interfere with septic tank function and can injure or kill fish and amphibians. This water may either drain into the ground surface, or be dechlorinated with vitamin C (ascorbic acid) or sodium thiosulfate before discharging to septic tanks or near water bodies. Do not let this chlorinated water enter wetlands, a stream, pond, or lake.

Flush. Once the disinfection sitting time is over, drain the chlorinated water from tanks and flush the distribution lines with fresh water beginning with the taps closest to the source(s). Flush the system until the taste and odor of chlorine is not objectionable or the free chlorine residual is reduced to the amount needed for taking coliform samples (see next item). Make sure you don't damage a pump by drawing water down below a pump intake level. If you have a storage tank, watch the water level in the tank to ensure you maintain at least 20 psi of pressure in the distribution lines to prevent a back-siphon event. When you flush, keep chlorinated water away from all surface water such as lakes, streams, or ponds (see sidebar).

Collect coliform samples. After disinfection, take a preseason "special" bacteriological sample for testing at a certified laboratory (marking it "special" on the lab slip means that the information will be reported to the water system only, and will not count as monthly routine monitoring). Collect this sample when:
  • There is zero free chlorine residual measured throughout the system in a system that is not continuously chlorinated.
  • The free chlorine residual is at whatever level is "normal" or required for a system that is continuously chlorinated.
Make sure the chlorine residual level has returned to the acceptable range before taking coliform samples or serving the water. Report on the seasonal startup checklist whether the test results came back positive or negative.

Make sure the chlorine residual level has returned to the acceptable range before taking coliform samples or serving the water. Report on the seasonal startup checklist whether the test results come back positive or negative.

Respond to unsatisfactory coliform samples. If a coliform sample tests positive, re-evaluate the water system for cross connections or openings that would allow bacteria to enter. Contact your water system regulator for appropriate actions (see further information below), such as addressing a problem and repeating the chlorination procedure.

Provide drinking water. Ideally, all sampling results will be satisfactory and the water system will be operating as it should before serving drinking water to the public. However, a system may open before obtaining absent coliform results. Work with your regulating agency for assistance. If your testing shows the presence of E. coli, a fecal coliform rather than just total coliform, it is best to remain closed while remedying the situation, but the system may still open with a Boil Water advisory posted for the public.

Ongoing Monitoring. All seasonal systems must now monitor for coliform each month rather than quarterly. It is best to collect these routine samples early in the month to allow time to take repeat samples within the same period should they be needed. Once into the operating season, if coliform results continue to show the presence of total coliform, the operator may need to complete and return a coliform investigation form (pdf).

Also wise to do during system start up: See Start-up To-do List.

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