A report in the Barnstable Patriot suggests that water conservation is raising the cost of drinking water in Hyannis, Massachusetts.
Edward F. Maroney reports that the Hyannis Water Board has at least temporarily closed a drinking water well because “a trace amount of perchlorate was detected.” Maroney does not report the amount except that it was “below that which would trigger a report.” The federally defined “Reference Dose” is 25 parts per billion (ppb) in drinking water, and under the US Environmental Protection Agency’s definition of the Reference Dose, anything between about 1/3rd to 3 times the published value — i.e., 8 and 75 ppb — is indistinguishable from 25 ppb.) Even this figure is highly precautionary because perchlorate has no observable effects at all in humans below about 250 ppb. (Meanwhile, Massachusetts has set a drinking water standard of 2 ppb, though the Commonwealth does not actually say that 25 ppb [or 75 ppb] is unsafe.)
In the same article, Maroney reports other news from the Hyannis Water Board suggesting that water conservation is not always beneficial, even on Cape Cod where the supply of ground water is limited:
The water board this week got good news on an improved flushing method that seems to be extracting a large amount of iron from the pipes. “The water got a lot cleaner,” said board chair Deb Krau.
The not-so-good news was that usage is falling off, a nationwide trend but one that could have significant impact on the Hyannis system’s rates and plans to replace ancient infrastructure.
All sort of reasons were raised at the Aug. 9 meeting: the down economy, use of water-saver technology such as low-flow shower heads, rate sensitivity, and even reluctance to put in home swimming pools because of liability issues.
“So we’ve really got to watch those numbers this year,” Krau said.
“The water board is trying to balance capital needs with the rates we charge,” [Department of Public Works Director Mark] Ells said in an interview. “So if it reaches the point where we don’t have adequate revenues, certainly that would impact other areas yet to be determined.”
What’s going on? Federal and State drinking water regulations require the Hyannis Water Board to make substantial capital investments to eliminate substances such as perchlorate. These investments have to be paid for by customers, which means higher rates generally. But as customers reduce consumption, whether due to higher rates or general invocations to conserve, the amount of water distributed declines. That means the costs of mandated investments in water treatment must be spread out over fewer gallons of water. If people continue to conserve, the Hyannis Water Board will have to charge even more for the same water. Which of course will lead to more conservation, and thence higher rates again.)
It can’t be discerned from Maroney’s article how much the Hyannis Water Board has had to spend to eliminate perchlorate. Nonetheless, we can be sure that it would spent less to achieve a less stringent but equally safe level, such as 25 ppb, 75 ppb, or even 250 ppb.
An estimate (with uncertainty spanning perhaps an order of magnitude) of a daily oral exposure to the human population (including sensitive subgroups) that is likely to be without an appreciable risk of deleterious effects during a lifetime. It can be derived from a NOAEL, LOAEL, or benchmark dose, with uncertainty factors generally applied to reflect limitations of the data used. Generally used in EPA’s noncancer health assessments.