posted on September 07, 2012 05:25
This article was first published in the Winter 2011 issue of Spigot News, the Ohio EPA's drinking water program newsletter. Many thanks for allowing us to republish it!
Ohio EPA conducts sanitary surveys once every three years at community public water systems (PWSs) and once every five years at noncommunity PWSs. The purpose of a sanitary survey is to evaluate and document the capability of a water system’s source, treatment, storage, distribution, operation and maintenance, and management; these all may adversely impact the ability of the system to reliably produce and distribute water that meets drinking water standards.
This article covers the sanitary survey or other investigatory site visits conducted at the water source and concentrates on the most common deficiencies found during the visit of small PWSs. Even though the article focuses on small systems, similar deficiencies can be found at larger public water systems. Future articles will cover treatment, distribution and other topics.
There are common deficiencies surveyors hope not to find when conducting a sanitary survey, or when following up on complaint investigations or responding to total coliform bacteria positive sample results. Figures 1 and 2 show poor water sources and figure 3 shows an acceptable water source. Figure 1 shows a well equipped with a sanitary seal which is missing bolts. It also shows that the casing is flush or in line with the finished grade, and the electrical wire and raw water line are exposed and unprotected. Although the well is vented, it does not have a screened vent. The well is also not protected from surface water runoff, other contaminants or critters.
Figure 2 shows a public water system well located in a parking lot. The well cap is missing bolts and therefore is not properly secured to the top of the well casing. There is also a depression surrounding the casing. If rainwater pools near the well, it can seep down along the casing and negatively impact the ground water and its quality. Located to the left of the well are bags of sodium chloride, which increases the potential for rust at the base of the well. Also, there is not enough protection around the well to prevent damage from motorized vehicles to the casing or electrical conduit.
Although you can’t see this in the picture, the well has a 1988 approved “National Sanitation Foundation” (NSF) well cap but it is not a “Water System Council” PAS-97 (or Pitless Adapter Standard, 1997) approved cap as required. The PAS-97 cap provides a properly screened vent which is not present in this cap.
Figure 3 shows an acceptable water source. The well casing extends approximately 24 inches above finished grade, which is beyond what is required (at least 12 inches above finished grade). The finished grade is sloped to drain surface water away from the well. The approved well cap fits flush over the top of the casing and electrical conduit; it provides a tight seal against the casing and prevents the entrance of water, dirt, animals, insects or other foreign matter. The well is also properly protected with concrete filled posts to protect it from motorized vehicles and mowers.