Lead Water Supply Lines/Entry Mains - Testing Problems/Advice

There are possible health hazards from lead content in water.

Depending  on the duration and extent of lead-water contact, lead can enter the water  supply if lead is present in supply piping or fixtures. Common sources of lead in water supply piping include older lead-bearing solder used on copper pipes, possible lead content in brass piping or fixtures, lead water supply piping (rare), and lead water supply entry main between a building and the public water main in the street (common in some areas).

Recently there was also a flurry of concern about lead contributed by brass  in private well pumps. However the testing methods used for this latter topic misrepresented an exaggerated and frankly dubious risk. Finally, it is possible  for lead to be found in private well water if lead contaminants have entered the  local aquifer.

Action Level

New York State Department of Health has set an action level  of 0.015 mg/L of lead in a sample of water drawn from a tap used for drinking water after a 6-hour period of no water use.

Variations in Lead Level vs. Testing Methods

Lead levels will usually be  quite high in water which has sat overnight in a lead line from street main to  house.

Most lab tests indicate low lead levels in water from such lines after the test fixture has run until all standing water in the piping has been flushed out  with fresh from the municipal supply mains in the street.

There are ambiguities in instrutions offered by some municipalities about how  to obtain a water sample for lead testing. The particulars of how the water  sample is taken can make a big difference in the lead level obtained.

1. The very first draw of water from a fixture is measuring lead contributed by any lead-containing brass which is present in some faucets.
2. "First draw" taken after a moment of flushing out the faucet is taking water from the pipes near the fixture. Depending on pipe material and length,  considerably more water might have to be taken before observing the water sample  exposed to most lead uptake.
3. First cold water after a night of no usage is likely to provide water that was sitting in the entry main from street to house. If this line is lead, the  lead content of this sample will be quite high. Alternatively, if all piping  were visible between the test fixture and water meter (rarely the case) one  could calculate the volume of water necessary to flush to obtain a sample from  the line to the street.
4. A water sample taken after running the water for several minutes (depending  on length of piping in the house from street to fixture) is sampling the quality of water provided by the municipality. Some city plumbing officials have expressed the opinion that lead oxide build-up in pipes insulates against  significant lead levels in water actively running through such lines.

Most local building codes do not require removal of lead, for example, the City of Poughkeepsie Building Codes do not require removal of residential lead supply lines (house to street). However eventually (usually after 40-60 years) these lines corrode, leak, and have to be replaced. Replacing the main supply  from street to the water meter, when required, could involve significant expense

People with concerns for the amount of lead in water should consult the local  health department and should have their water tested for lead. Typical lab fees are $20. to $25. per sample plus the cost of hiring an independent consultant to collect and handle the water sample if you don't do it yourself.

Even if you are not concerned with testing for lead in water it would be wise  to reduce possible lead intake by flushing any lead-containing piping before  drinking such water. In addition, lead-in-water removal equipment is available  from water treatment companies.

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