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EPA in Illinois

Water Testing Recommendations for Chicago Residents

See also Advice to Chicago Residents About Lead in Drinking Water

Water sampling recommendations and instructions depend on whether you have a lead service line. A 2013 study shows that the existing sampling protocol underestimates lead levels in drinking water at homes with lead service lines. The study of 32 single-family homes with lead service lines was conducted by EPA Region 5 in partnership with the City of Chicago.

To keep sampling affordable and simple, and to provide information that we believe will be useful, we recommend that for homes with lead service lines, you collect a water sample after following the recommended flushing instructions. These results would show typical lead levels once you’ve flushed your plumbing to remove the highest lead levels from the drinking water.

How to collect the sample

You should collect the sample after water throughout the household has not been used for at least 6 hours (example: midnight to 6am). During these 6 hours, do not use any water in the home (no flushing toilets, showering, doing dishes or laundry) since this will affect the lead-testing results.

The best time to collect a sample is either:
  1. First thing in the morning, before any water is used in the household; or
  2. Immediately upon returning from work, and before using any water, as long as water has not been used in the household during the day.

When you are ready to collect your sample, collect a cold water sample from the kitchen tap.

Plastic sample bottle with illustration indicating fill line

If no portion of your home’s service line is made of lead:

  1. Do not remove the aerator from the faucet.
  2. Do not run any water from the tap before collecting the sample.
  3. Place the opened sample bottle below the faucet.
  4. Gently but fully open the cold water tap.
  5. Fill the sample bottle up to the neck of the bottle.
  6. Turn off the water and tightly cap the sample bottle.

If any portion of your home’s service line is made of lead:

You will need to flush the plumbing just before taking the sample.

  1. Do not remove the aerator from the faucet.
  2. Remove the cap from the sample bottle, so that you have the bottle ready.
  3. Gently but fully open the cold water tap.
  4. Do not take the sample yet. Let the water run for 3 or 5 minutes. NOTE: If the water flows slowly in your home, the water needs to run for at least 5 minutes.
  5. After running the water for 3 or 5 minutes, place the opened sample bottle below the faucet.
  6. Fill the sample bottle up to the neck of the bottle.
  7. Turn off the water and tightly cap the sample bottle.