In July of 2010 the EPA requested comments on proposed changes to the

Total Coliform Rule.  The entire posting can be read on this link.

Federal Register / Vol. 75, No. 134 / Wednesday, July 14, 2010 / Proposed Rules

I have posted the most interesting part (at least to me).

2. Storage Tank Inspection and Cleaning EPA requests comment on the value and cost of periodic storage tank inspection and cleaning. There are instances of storage tanks being the source of waterborne disease outbreaks at PWSs. In December 1993, a Salmonella typhimurium outbreak in Gideon, Missouri resulted in over 600 people affected by diarrhea, 31 cases of laboratory-confirmed salmonellosis and seven deaths of nursing home residents who had exhibited diarrheal illness (four deaths were confirmed by culture). The larger of the two storage tanks had a breach in the roof hatch that allowed pigeon droppings to be carried into the tank and likely accumulated in the several inches of sediment. This contaminated sediment, more than likely, was pulled into the distribution system by a flushing program that  drained the tank (Clark et al. 1996). Salmonella typhimurium was isolated from the sediment of one of the towers, and tap water tested positive for fecal coliforms (CDC 1996). In March 2008, Alamosa, Colorado (with a population of about 9,000 people) experienced a waterborne disease outbreak associated with Salmonella. The report released by the Colorado Department of Public Health and Environment (Falco and Williams 2009) indicated that the outbreak resulted in 442 reported cases of illnesses, 122 of which were laboratory confirmed, and one fatality. The State epidemiologist estimated that a total of 1,300 people may have been ill. Two storage tanks in Alamosa had several inches of sediment and breaches; one tank had breaches large enough for birds and animals to enter. Some of the key factors that contributed to these two outbreaks include significant levels of sediment (several inches to feet) and the presence of breaches of the integrity of the storage tank. Sediment accumulation occurs within storage facilities due to quiescent conditions which promote particle setting. Over time sediment continues to accumulate in a tank, even if the finished water is consistently treated tobelow 0.1 nephelometric turbidity unit(NTU). For surface water systems, it isnot uncommon to have 1⁄4 to 1⁄2 inch or more of sediment accumulate after two to three years (Kirmeyer et al. 1999).

While there are no turbidity regulations for ground water systems (except for ground water under the direct influence of surface water (GWUDI)), the levels of turbidity can be significant in the water pumped from an aquifer. Sand particles, if allowed to accumulate, provide pore spaces that house diverse populations ofbiota (which may include pathogenic microorganisms) (Kirmeyer et al. 1999; van der Kooij 2003). Periodic high flows in the storage tank may scour, stir up, and suspend the sediment (along with entrapped bacteria and pathogens) and carry it into the distribution system, with greater accumulation of sediment being a more significant concern. Other water quality problems associated with sediment accumulation include increased disinfectant demand and disinfection byproduct formation. The storage tank’s vulnerability to contamination increases when breaches of the storage tank allow insects, animals, and birds and their associated diseases to enter. Contamination from bird and other animal excrement can potentially transmit disease-causing organisms to the finished water.  Waterfowl, for example, are known carriers of many different waterborne pathogens including Vibrio cholerae(Ogg et al. 1989). Based on the potential public health implications associated with poorly maintained storage tanks (e.g., as indicated by significant sediment accumulation and breaches), EPA is interested in receiving comments and supporting information regarding the state and condition of tanks that have been cleaned and inspected, costs of storage tank inspection and cleaning, and how public health can be better protected. EPA requests information on whether there are States that recommend or require periodic inspection and cleaning of storage tanks. If so, what are the requirements, the frequency of inspection and cleaning, and how successful are they? Are inspections and cleaning done by individual PWSs or by contractors?

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The EPA extended the comment period until October 13, 2010.


Photos & comment from Ron Perrin:

Sediment Being removed from the floor of a water storage tank

Three inches of sediment being removed from a water tower.

Over time sediment builds up in almost all water storage tanks.  Only with annual inspection of the tanks can the utility operators know they have a problem with sediment levels or a possible breach in the tank.  The most common breach is missing or corroded vent screens.  In areas in the US where tanks are rarely or never inspected it is more common to see water storage tanks & towers with holes in the roof allowing insects and birds to enter the tank.

This sediment that builds up in the floor of the tank can become a breeding ground for bacteria, protozoa and even viruses.  As contaminants become a problem, the water utilities add more and more chlorine and other treatment chemicals. This kills living organisms but starts to build up chemical byproducts like chloroform, trihalomethanes, bromoform, and other contaminants that have been linked to cancer.

Removing the sediment in the floor of water storage tanks is the best way to keep them healthy.  It takes less treatment chemicals, less treatment chemicals means less chemical by-products in our water.  Please join me in responding to the EPA request for comment.  Let them know there should be rules to inspect and clean all water storage tanks that serve water to the public.

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Related Information:

The New York Times has a series of articles called “Toxic Waters” about the worsening pollution in American waters and regulators’ response.  Read more at this link:

That Tap Water Is Legal but May Be Unhealthy By CHARLES DUHIGG Published: December 17, 2009

What’s in Your Water

The 35-year-old federal law regulating tap water is so out of date that the water Americans drink can pose what scientists say are serious health risks — and still be legal. Examine whether contaminants in your water supply met two standards: the legal limits established by the Safe Drinking Water Act, and the typically stricter health guidelines. The data was collected by an advocacy organization, the Environmental Working Group, who shared it with The Times.  See the link below:

What is in your water? Find water Quality reports here: