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Investigative Sampling for Lead in Drinking Water

man holding sampling bottle next to school drinking water bottle filling stations
Environment, Great Lakes, and Energy

Investigative Sampling for Lead in Drinking Water

Schools and child care facilities either get their source of water from a community water supplier or they produce their own water on site. Schools and child care facilities that have their own water source must follow the Michigan Safe Drinking Water Act, 1976 PA 399, as amended (Act 399), Lead and Copper Rule requirements for lead and copper sampling.

Schools and child care facilities that get water from a community water supplier should voluntarily take steps to test and reduce the risk of lead in drinking water using guidance from the United States Food and Drug Administration (FDA) and EGLE.

There is no known safe level of lead exposure for children. EGLE recommends that action is taken to reduce the risk of lead in water at all fixtures with test results greater than 5 parts per billion (ppb) and encourages schools and childcare facilities to reduce lead levels to the lowest possible amounts.

The potential for lead to be released into water increases the longer the water remains in contact with leaded plumbing materials and, as a result, facilities with intermittent water use patterns, such as schools, are more likely to have elevated lead levels in drinking water.

The occurrence and rate of lead release into drinking water depends on:

  • How corrosive the water is (corrosivity is a function of water quality and can be measured through pH, alkalinity, conductivity, etc.)
  • The type of plumbing materials in the building (leaded solder, lead pipes, brass valves, etc.)
  • The age of plumbing materials (pipes pre-1989 and fixtures pre-2014)
  • How long water sits in pipes and fixtures (weekends, vacation breaks, and low usage taps)
  • If solid pieces of pipe scale containing lead (particulate lead) are knocked loose or disturbed, very high lead results can occur
two lead sampling bottles

Investigative Sampling for Lead

A plan for investigative sampling for lead should be made with the goal of sampling all fixtures where water is used for drinking or food preparation.

Schools and child care facilities that get water from community water supplies and nontransient noncommunity facilities can conduct investigative sampling for lead in drinking water.

The risk of lead in drinking water may still exist even if the building does not have a lead service line or lead solder because lead is still allowed in small amounts (up to 0.25 percent) in brass valves, “lead-free” fixtures, and other plumbing components.

Lead may be found in the plumbing system building-wide, or just at a single fixture – you will not know unless every fixture is tested. Lead release can be variable. An initial test at a fixture may show no lead but if the conditions are right (i.e. excessive stagnation or particulate release), another sample taken at the same fixture later may show elevated results. Do not include fixtures that are not used for consumptive purposes (e.g., hand wash, janitor, lab faucets, etc.) in the sampling plan; however, clear signage should be used at these locations to notify people that it is not for drinking.

bottles of samples in trunk of car

How frequently your facility can and should test for lead in drinking water is dependent on a variety of factors (e.g., plumbing, water quality, lead results, budget, and competing priorities). Schools and childcare facilities should make drinking water testing a part of their regular building operations. Annual monitoring is suggested as it provides information on changes in the lead levels and the effectiveness of remediation or treatment efforts.

Lead sampling priorities:

  • Buildings with the highest risk population (ages six and under)
  • Fixtures used by children under the age of six or pregnant women
  • Schools or childcare facilities built before 1989
  • Fixtures that are older and/or have never been tested
  • Fixtures frequently used by students and staff
8 happy school children

Guidance for Lead Reduction in Schools and Child Care Facilities

Michigan uses the United States Environmental Protection Agency (EPA) 3Ts  For Reducing Lead in Drinking Water in Schools and Child Care Facilities manual as a model for creating a program, testing for lead, communicating the results, and taking remediation actions where needed.

Additional EGLE guidance documents and information are also available for download.

Visit the EPA's 3Ts for Reducing Lead in Drinking Water for detailed information and to download:

In general, there are ten steps to take for lead reduction in school and child care drinking water outlined the 10 Steps to School & Child Care Water Testing.

EGLE recommends that all fixtures used for consumption are sampled and tested for lead, however, a school or childcare facility conducting investigative lead sampling may decide to prioritize the sampling effort if resources are limited. If this is the case, prioritization should be made at buildings with the highest risk for lead release and those with the youngest children.

Follow up samples should be taken after all remediation efforts are completed to ensure low lead results before a fixture is put back into service.

Lead Sampling Considerations

Meaningful results can be obtained only if the samples are collected properly. EGLE recommends the following sampling considerations based on the EPA’s 3Ts for Reducing Lead in Drinking Water in Schools and Child Care Facilities manual, specifically Modules 4 and 5.

water drop with sign that reads, "Do Not Drink from this Sink" and "Water Testing in Progress"
  • Have a communication plan in place before sampling.
  • Select a Michigan certified laboratory to analyze the samples for lead.
  • Collect samples only from fixtures for drinking or food preparation.
  • Sample on a day during the week when school is in session or on a Saturday.

Lead Sampling Procedures

EPA recently released the “Lead Sample Collection Field Guide” for specifics on lead sampling along with a video and additional sampling trackers.

General Steps to Collecting Investigative Samples for Lead

two lead sampling bottles
  • Use 250 milliliter (mL) wide-mouth bottles from a certified laboratory.
  • Make sure no water is used in the building for a minimum of eight hours before sampling.
  • Do not let any water run down the drain when collecting a first-draw sample.
  • A 30-second flush sample may be collected after the first-draw sample.
water fountain and bottle filler with fixture identification code
  • Collect only cold water.
  • Collect samples in order of the sampling plan (sequential sampling).
  • Do not remove aerators or screens prior to sampling.
  • Do not flush the system prior to sampling unless instructed to do so.
cardboard box cooler with drinking water samples inside
  • Do not close shut-off valves to prevent fixture use prior to sampling.
  • Follow laboratory requirements for sample delivery.
  • Know what actions you will take if test results show elevated lead.
  • Communicate the results and actions to the school community.

Interpreting Lead Test Results

examples of EGLE drinking water lab results

It is very important to review and understand the meaning of all test results immediately upon receipt from the laboratory. The sample results should be compared to the plumbing profile, any field notes taken during the sampling event, and any previous test results as they may help explain the reason for the result, give you a “big picture” of what may be going on with the plumbing system, help in corrective actions if needed and provide meaningful information to reduce the exposure and risk of lead in drinking water. For example, if the field notes show an aerator is full of particles when you check it after you collected the sample, and the result shows elevated lead amounts, you may have found the cause of the lead in the water at this fixture and simple cleaning and resampling may correct the problem. Also be aware that a non-detected lead test result may not be meaningful if the field notes indicate that the faucet was leaking during sample collection.

person reviewing a fixture plan

A review of the test results for all fixtures used for human consumption in a building will indicate whether there is a building-wide risk of lead exposure in the drinking water, if it is an isolated case, or if there is no risk.

example of lab test results for drinking water

When the laboratory returns the test results, the concentrations of lead in the drinking water samples will be reported in metric form such as milligrams per liter (mg/L), micrograms per liter (ug/L), or they will be reported as a concentration such as parts per million (ppm) or parts per billion (ppb).

Milligrams per liter (mg/L) is the same as parts per million (ppm).

Micrograms per liter (ug/L) is the same as parts per billion (ppb).


  • 0.001 mg/L = 1 ug/L = 0.001 ppm = 1 ppb
  • 0.005 mg/L = 5 ug/L = 0.005 ppm = 5 ppb
  • 0.015 mg/L = 15 ug/L = 0.015 ppm = 15 ppb

EGLE recommends that schools and childcare facilities take immediate action to reduce the amount of lead in drinking water at any fixture with a result greater than 5 ppb, which is the U.S. Department of Agriculture’s health standard for bottled water.

outside of a school

After obtaining the test results, it is important to provide the results to the school community as soon as they are available. You also need to communicate the actions you will take to reduce the risk of lead in drinking water if you get elevated lead results, or if no corrective measures are appropriate because the lead levels are low.

two lead sampling bottles

Testing Follow Up

There are things that must be done to make sure actions taken to reduce lead and improve water quality have been and continue to be successful:

  • Collect follow up samples after all remediation efforts to ensure no to low lead results before a fixture is put back into service
  • Update documents and records
  • Provide parent and staff outreach
  • Provide proper maintenance on filtration devices
  • Conduct routine sampling on a regular basis to ensure water quality