Best Practices for Location, Source, and Preliminary Pretreatment for Raw Water

  • • Review the information above on General and Specific Sources of Contamination and Best Practices for Prevention, Mitigation and Control and implement the Best Practices which relate to the potential problems found in a given locality.
  • • Utilize the Best Practices from the private drinking water systems that apply to the public drinking water systems, especially those related to the use of groundwater as the raw water source.
  • • Conduct a survey to determine the degree of pollution from all sources entering the watershed and evaluate whether or not the raw water source can be utilized and if so what treatment would be necessary to make it safe and meet all of the minimum specifications of the US EPA and other authorizing agencies.
  • • Pesticides or herbicides used within the watershed must be used with strict adherence to all posted directions on labels and label restrictions.
  • • The water quality microbiologically, chemically, and physically must be established from various tests as well as the quantity of water which will be taken on a daily, weekly, monthly, and yearly basis and how this quantity will be replenished must be supplied to the authorizing authority when requesting a new raw water source.
  • • The water must be continuously monitored at the surface water intakes microbiologically, chemically, and physically and appropriate action must be taken immediately if the tests show the water exceeds any of the established regulations by the US EPA or local authorizing authority.
  • • Intakes must be located away from swamps and other areas where contamination could readily enter the raw water supply. The intakes must be protected against objects coming down through the water which could damage them.
  • • Establish a 200-foot radius restricted zone, which has appropriate signs warning people engaged in all recreational activities to stay outside of the special area.
  • • Keep all raw water inlets at least 1000 feet away from boat launching, marinas, docks, or floating fishing piers.
  • • The raw water should be taken from several different depths of the surface body of water, which can reduce turbidity caused by storms and also give a different quality of water from each depth.
  • • Put the raw water intake valve for the water treatment plant away from the source of water feeding the surface body of water. This will also reduce the level of turbidity in the raw water.
  • • If the raw water source is a river, make sure that there are no pipes within a reasonable distance discharging pollutants into the river upstream from the water intake area.
  • • Use screens or grates to reduce the amount of debris entering the water treatment plant.
  • • Keep all water intakes upstream from a sewage treatment plant or any other industrial plant and at least 500 feet away.
  • • Use a settling pond or concrete basin for presedimentation of the raw water especially if the source has a lot of sand and gravel in the water. Allow a detention time of at least 20 minutes and clean out the pond or concrete basin frequently. Organic polymers may be added to increase the amount of presedimentation.
  • • Develop a raw water pump station facility in a well-drained area and above any possible flood stage. It should stay in operation during flooding events. The building should be locked and enclosed by a fence which cannot be tampered with by intruders.
  • • An all-weather road should be constructed leading from main roads and highways to the raw water pumping station.
  • • The raw water enters the treatment plant and has added to it alum, iron salts, or synthetic organic polymers which bond with metals and salts to cause the small particles present in the raw water to become large particles and then settle to the bottom of the tank. Different types of filtration media as well as ion exchange for inorganic contaminants and absorption for organic contaminants follow this. The water is then either disinfected with chlorine or ozone, with chlorine being by far the most common disinfectant used.
  • • Develop a comprehensive cyanotoxin management plan. (See “Cyanotoxin Management Plan in the Programs” section below for a model program.)
  • • All marinas and docks must provide special facilities for proper sewage, and solid and hazardous waste disposal facilities.
  • • All on-site sewage systems and sewer manholes must be a minimum of 75 feet from the highest level the water source will reach on land and must be protected against flooding at the anticipated 50-year flood level.
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