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The subject of lead leaching from pipes and faucets into drinking water within buildings is not new. But the broad growth of green buildings, including green schools, that include water conservation strategies has the potential to negatively impact the quality of drinking water in those green building plumbing systems.

To reduce indoor water consumption, LEED v4 New Construction offers points for further reducing by 25% and up to 50% “fixture and fitting water use from the calculated baseline in WE Prerequisite Indoor Water Use Reduction.”

But the consequences of that reduced water have lead to concerns across the country including in green schools from the West coast to the East coast.

Some of the difficulty in characterizing this water quality and public health issue is there are not any quantity of good studies of existing building, including schools. As required by the 1974 Safe Drinking Water Act, the U.S. Environmental Protection Agency developed a guidance program that instructs 20 parts per billion (or 0.020 mg/l) is the recommended “action level” for the amount of lead in drinking water that specifically applies in evaluating sampling results from schools and day care facilities. EPA recommends that schools and facilities take additional actions to evaluate and address specific problem areas (e.g., faucets and fountains) for which the sampling results show an exceedance of this level. But the federal law and no state law that this writer is aware of requires a school to take a sample or test the water.

Note, that level is significantly higher than the 15 ppb (or 0.015 mg/l) for lead allowed in a “public water system.” EPA requires annual testing for lead under the SDWA for water provided by public water systems. A public water system is defined in part as a system for the provision to the public of water for human consumption through pipes or other constructed conveyances that serves at least 15 service connections or regularly serves at least 25 individuals. So unless a school has its own water supply (and few do), schools are not a regulated public water system.

So, there is little data. But, concerns from Oregon to Maryland have resulted in testing of both the quality of water coming into the green school building and at water fountains and other outlets used for consumption. And water fountains and other outlets are being taken out of service where the lead level exceeds 20 ppb.

Despite no good baseline for comparison, there are clear trends that go beyond lead alone. Among the most significant culprit is apparently “water age” (i.e., the water retention time). The green school buildings sampled had exceptionally high water age, and it appears that elevated water age is inherent in achieving sustainability goals of green building plumbing systems.

The magnitude is daunting. The first green building for which this firm reviewed data has water use which is more than 50 times lower a typical similar building. Very low use at each fixture in bathrooms, coupled with large diameter pipes stipulated by plumbing code, resulted in an average overall premise plumbing water age of 8 days.

Water age of 8 days raises concerns with respect to the chemical and microbiological stability of the drinking water.

There are externalities associated with water age, including that a disinfectant residual (e.g., a residual level of chlorine) was generally not maintained in the plumbing of the green buildings. At that first green school, 40 minutes of flushing was necessary to establish a chloramine residual similar to that present in the public water system.

Most immediately, regular flushing of water is a practical approach to addressing water quality in green buildings including green schools.

It is anecdotally reported that a LEED Gold certified school with very high water age solved problems with elevated lead and microbial growth by regularly flushing a small volume of water (3 minutes of flushing every 6 hours, less than 1% of the total daily flow into the building) to regularly introduce fresh water into the system.

While wasting water may be viewed to conflict with the conservation goals of green building, it may serve as a temporary solution to the apparent public health issue.

This is a tough subject. Have the green building programs gotten ahead of reliable science in the area of water quality?

More and additional research is needed now from the environmental industrial complex to assist in justifying potable water conservation goals without compromising water quality and the public health. All schools and day care centers should test for lead in drinking water.

And you might want to test the water in your green building for lead.