Water Testing

Milwaukee Water Works regularly tests water at homes with lead service lines for the presence of lead. Homes with lead pipes show low levels of lead. The federal Lead & Copper Rule requires utilities to test the water at residential properties for lead every three years. The graphs below provide a visual representation of the results of these tests. Water Works conducts additional testing every year of properties when lead service lines are replaced, both before and after the service line replacement. 

The graph below shows the results of Milwaukee's lead sampling results conducted in accordance with the federal Lead & Copper Rule from 1993 - 2023. 

-For a list of individual test results at 51 residential properties where samples were collected for 2023 Lead & Copper Rule compliance, click here.  
-For a list of individual test results at 52 residential properties where samples were collected for 2020 Lead & Copper Rule compliance, click here. 
-For a list of individual test results at 50 residential properties where samples were collected for 2017 Lead & Copper Rule compliance, click here.

 

For the results of our 2022 and 2023 testing at residential properties prior to replacement of a lead service line, click here.
For the results of our 2022 and 2023 testing at residential properties after replacement of a lead service line, click here.

For all 2022 and 2023 retest data, click here.

Notes about results:
1.    When a lab reports test data, they include a ‘reporting limit’. This means that their equipment and method is less accurate below that level. Below that level, they can confirm the results are relatively low, but exactly how low would only be an estimate. Reporting limits are typically determined at least once a year through testing and/or statistical review of data but may also be changed more frequently if there is a significant change in the equipment or method. Since our samples have been tested in different labs at different times, the reporting limits vary.
2.    BRL = below reporting limit. This means the result reported was below the lab’s limit as described above.
3.    Re-tests are always offered after a high lead result. Customers are asked to remove and clean faucet screens (aerators) and flush all the plumbing in the home in case the source of elevated lead is particles that are caught in the plumbing. A new test kit is provided to confirm if that helped, and to help identify where the source may be. If the issue is not resolved, additional referrals are made.
4.    Addresses are approximate only. If your home was tested for lead, a results letter was sent to the property. 

Three bottle testing procedure:
•    Bottle number 1 is used for the first water collected after turning on the faucet, usually after the water sat stagnant in the pipes for at least six hours. This represents the lead that can leach from internal plumbing and faucets.
•    Bottle number 2 is used for the water collected 45 seconds after bottle number 1 (with the water flowing during that time). This is intended to collect the water that was stagnant in the service line during the stagnation period. In rare cases, lead particles caught in faucet screens or other lead sources in internal plumbing can transfer to this sample as the water flows through the plumbing.
•    Bottle number 3 is used for the water collected 3 minutes after bottle number 2 (with the water flowing during that time). This is intended to collect fresh water entering from the water main in the street. In rare cases, lead particles caught in faucet screens or other lead sources such as service lines or internal plumbing can transfer to this sample as the water flows through the plumbing.
•    The three bottle testing procedure is based on the average plumbing of a single-family home. If a home is larger or has a longer service line, the timing may not work out as intended.

The EPA action level for lead in water is 15 µg/L. (micrograms per Liter)

The recently finalized Lead and Copper Rule Improvements change this level to 10 µg/L. The compliance date for this new level is November 1, 2027.

Different labs use different testing methods and equipment, which can result in different reporting limits. This means you could receive a result with this symbol before it: < (example result: <1 µg/L). The ‘<’ symbol means ‘less than,’ which indicates that the lab’s method cannot report numbers below that level (this is their reporting limit). The lab has confirmed that your result is between zero and their reporting limit, but they can’t report anything more specific because their equipment can’t detect amounts less than 1.

How you collect your sample affects what you learn about your water. Most labs will recommend you let the water sit unused in the pipes for at least 6-8 hours before collection. This is to simulate the worst-case scenario for lead, since it gives time for lead to leach from the pipes into the water. If this is your method, be sure you are not flushing the toilet, running the washing machine or using any other water in the home during those 6-8 hours.

• If you collect a ‘first draw’ sample (the first water that comes out of the faucet after 6-8 hours), any lead you measure is likely leaching from your internal plumbing and fixtures.
• If you let the water run for about 45 seconds to 1 minute, any lead you may detect and measure is likely leaching from your service line (the pipe that connects your home to the water main in the street).
• If you let the water run for about 3 minutes or longer, it is more representative of the water in the water main. Note: These timings assume typical length of plumbing for a single family home.
• Always collect samples from the cold-water tap in your kitchen or bathroom (where you would normally get drinking water from). Hot tap water should NOT be used for drinking or cooking because hot water heaters can contribute contaminants to your water.