::. Water Analysis

The Community Health Branch (CHB), DOHS, supports the ORFDO in maintaining the quality of drinking water at the NIH by sampling drinking water for concentrations of lead, as needed. CHB maintains records of sampling results and their corresponding locations to aid in responding to inquires concerning drinking water quality.

Water supplied to the NIH comes from the Washington Suburban Sanitary Commission Potomac water filtration plant. The same water also supplies the communities surrounding NIH. Public water systems are required by Federal Law through the Safe Drinking Water Act to ensure that the water distribution systems under their control do not contribute harmful concentrations of lead.

Lead can enter the drinking water system in two ways - from source water and through the interaction of water with plumbing materials containing lead. Lead from source water is not generally a problem where the water is supplied by a public water system. Most of the lead in drinking water enters from plumbing materials such as solder, fluxes, pipes and pipe fittings; fixtures such as some brass faucets; and from sediment. In 1986 Congress passed amendments to the Safe Drinking Water Act, including the Lead Ban, which requires that only lead-free materials be used in new plumbing and in plumbing repairs.

The concentration of lead in water is also a function of how long water is left to sit in a line. Lead can be a problem in systems where water is left to sit without being used for long periods of time. Routine use of the water reduces the amount of lead that can accumulate in the water. Samples from fountains are collected as a “morning, first-draw” water sample. The “morning, first draw” sample is the first plug of water emitted from a fountain after the water has sat overnight and most often contains the highest concentrations of lead. These samples generally represent the “worst case” situation. Lead concentrations decrease rapidly as water flows through the lines. Therefore, individuals may reduce their intake of lead by flushing the system for 10-15 seconds before drinking.

For the evaluation of acceptable lead levels, the NIH has adopted the EPA trigger level of 20 parts per billion (ppb)recommended by the US Environmental Protection Agencyin "Lead in Drinking Water in Schools and Non-Residential Buildings" (EPA 812-B-94-002, April 1994).

In areas at NIH where the lead in drinking water levels is found to be greater than 20 ppb, the ORFDO will supply bottled water until such a time as the lead levels are reduced to below 20 ppb. Typical control measures to reduce lead concentrations include flushing the system or water fountain; cleaning the strainers; re-piping; and/or replacing the water fountain.