How lead enters the water supply: lead testing & repair advice.

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).

Action Level for Lead in Water - allowable lead limits

Readers of this article should see our review of a Home Test Kit for Lead in on building surfaces located

at LEAD TEST KIT for HOME USE. The same company offers a lead-in-water test, as do local health departments and private water testing labs in most cities.

Also
see LEAD CONTAMINATION in DRINKING WATER: Testing & Correction - Advice.

Health hazards from lead content in water

An example of lead water supply piping at the building water main supply pipe is shown in our photo at left. Just how much lead this pipe contributes to the building water supply depends on several variables that we discuss along with additional photos of lead water supply (and drain) piping
at LEAD PIPES in BUILDINGS.

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.

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.

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. Home test kits for lead cost around $10.00.

See LEAD TEST KIT for HOME USE.

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.

List of Common Remedies for Lead in Drinking Water

• Private drinking water well water treatment systems can be installed to remove lead in drinking water
• Replace lead supply piping running through the building
• Replace lead entry main water supply piping - we recommend deferring this costly repair until the water pipe needs replacement due to wear, damage, or leaks. In the interim a thorough flush-out of the supply piping before taking drinking water for consumption will normally reduce the lead level in drinking water to extremely low levels, possibly below the limits of detection.
  
  We discuss this effect at LEAD CONTAMINATION in WATER, HOW to TEST. (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.)
• Install point of use small water purification systems such as at the building kitchen
• Other lead hazards, such as lead paint, are discussed at LEAD CONTAMINATION HAZARDS in the HOME

Reader Question: How accurate is First Draw Advice for Testing Water for Lead Levels

My town is conducting a lead in water survey and wants me to take the first draw water out of one of our faucets when we get up in the morning. Is this the most accurate way to determine our family's exposure to lead in drinking water? - Anon. 1/13/2012

Reply:

Watch out: if there is lead exposed to water passing through a water system then the results of a test of water for lead levels can vary drastically depending on many variables. However you should follow the water testing protocol recommended by your local health department or municipal authority. Otherwise your test results cannot be joined in any study of buildings or homes in your community.

However with a bit of research one can also construct a best case (minimum level of lead likely to be detected in water) and a worst case (likely to detect highest level of lead in drinking water). You can conduct those additional lead tests in order to get an idea of the bounds of possible lead exposure from drinking water in your building.

Keep in mind that even these cases may vary over time as water temperatures and water chemistry will vary even if the lead exposure remains constant.

Lead-in-Water Testing Protocol for Best & Worst Case Scenarios

OPINION-DF: based on direct participation in a lead in water test program:

This s anecdotal report explains the difficulty of giving lead-in-water water test protocols to homeowners.

Interestingly I have actually done some tests on the effects on measurable lead levels of water line flushing, as I participated in a municipal water supply lead testing program a while back in 1995.

Some testing protocol instructions advise the homeowner to collect first-draw water samples after a night of no water running.  That can be a mistake and can give misleading results as these four cases explain:

1. If the water supply pipes immediately adjacent to the sink were made of lead
   
   or included copper sweat fittings that used high-lead solder, that might be the worst case or highest lead level in water for that building. But it might not.
2. If the in-building water supply pipes are not lead (which is more often the case in most buildings in North America) and if nevertheless there is a lead water entry main
   
   at the home (the water pipe between the street water main and the building water piping), then to check for the "worst case" or highest lead level we took the first COLD draw - which was water that rested in the building's individual entry main water pipe overnight.
3. If the municipality's own water mains include lead piping
   
   then those pipes too provide a source of lead in water and will confound water testing protocols.
4. If the building water supply is from a private well and the water source itself is high in lead,
   
   that will confound attempts to trace lead levels to specific water piping - a condition that can be verified by direct sampling of the well water in different seasons.

After that was flushed for a time sufficient to know I had water from the (non lead) main in the street I took a second sample.

1. The first draw water test sample was very low in lead
   
   (this was water in galvanized iron pipes or in other homes copper. On a few occasions one can pick up lead from internal faucet parts but that's getting pretty rare).
2. The first cold draw water sample was very high in lead
   
   (water that sat in the entry main overnight)
3. The well-flushed cold draw water sample was below any action level for lead content.

When I sent in my high-lead sample to the city, and before I had explained my sampling protocol, the city rep found the results remarkable as they were inconsistent with similar homes on the same street.

We know you did something ... but we can't figure out what. We want to do the lead test again after we flush the water mains at your street's hydrant.

In response to our water sample's very high lead level, the city wanted to do the test over again with a new protocol.

The rep proposed to open a hydrant on the street, flush the water mains, then have me flush the house plumbing then collect a sample of water to test for lead level - what I call a "best case or lowest risk" sample. Their object was to force the building to pass the test (perhaps avoiding an expensive change to the city water chemistry managing equipment in order to reduce lead leaching rates.)

My reply was

OK, Fine. But you'll have to promise that every morning before anyone in the city gets up to brush their teeth or draw a glass of water you are going to flush out every water main and building water supply piping system in the city.

which was the end of that.

It is apparent that one cannot give a single quantitative guide on water flushing as where lead pipes are in the system, pipe length, pipe diameter, water aggressivity, water flow rates, and similar factors all introduce so many variables.

That's what underlies my OPINION that just telling people to flush out their water lines is actually dangerous. In the worst case someone will feed their baby the first COLD draw from a lead entry main.

...

Continue reading at LEAD CONTAMINATION in WATER, TEST or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• LEAD IN DRINKING WATER, HOW to REDUCE
• LEAD PIPES in BUILDINGS
• LEAD CONTAMINATION HAZARDS in the HOME - home
• LEAD CONTAMINATION in WATER, TEST
• WATER TREATMENT EQUIPMENT DISINFECTION

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LEAD in WATER, ACTION LEVELS at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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INDEX to RELATED ARTICLES: ARTICLE INDEX to WATER TESTING

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