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Water Mains: Replacement and Maintenance

To report water running in the street - which could indicate a main break - please call our 24-hour Control Center at (414) 286-3710.

Standing water, water pooling up in the street or water running down the street can indicate a water leak in a main or a service line. At any time, customers may report such water conditions for investigatiion to the Milwaukee Water Works 24-hour Control Center at (414) 286-3710.


A main break may also result in temporary water shutoff to customers served by the main. The repair crew goes door-to door telling customers to prepare for a water shutoff by filling a few containers with water for temporary use. Customers who do not answer receive a door hanger. To avoid disturbing customers, the utility does not provide direct notification between 10 p.m. and 6 a.m. At any time, customers may call the Milwaukee Water Works 24-hour Control Center at (414) 286-3710 for information about the status of a repair.


Lead service lines are replaced when the service line itself is found to be leaking, or during planned water main replacement projects. Main breaks are routinely repaired with no impact to water service lines. Before the temporary water shutoff, Milwaukee Water Works (MWW) Distribution staff check MWW records of properties in the area to be shut off to identify water service lines that are made of lead or copper. At properties with a lead service line, MWW leaves a door hanger that serves as a voucher for one filter pitcher and includes instructions for flushing household plumbing, and a Lead-Safe Water Guide brochure. The voucher can be exchanged at the customer’s discretion for one filter pitcher by presenting it aProperties in the shut-off area with a copper service line receive a door hanger advising them to flush their household plumbing after the water is turned back on.

Water Main Replacement Program
Investing in water main replacement is paying off. We're seeing a downward trend in the number of main breaks per year since the 1970s. The chart shows an exception when the winter of 2013-2014 set record-breaking, long periods of extreme cold, which caused more main breaks than normal. Here is a chart showing 5- and 10-year main break averages from 2009-2018.

New mains made of ductile iron pipe are designed to last over 100 years. They provide reliability of service, continued high quality water, and plenty of water pressure. The cost to replace one mile of water main is approximately $1.3 million. There is no special assessment to property owners.

The Capital Improvements Program prioritizes projects based on results of water-related research, new technology, and condition assessment of existing systems. Revenue from water rates partially funds capital projects, and Milwaukee Water Works capital projects are funded in part by the Wisconsin Safe Drinking Water Loan Program administered by the Wisconsin Department of Natural Resources.

We have a long-range plan to replace aging water mains. Fifteen miles of main were completed each year, 2015, 2016 and 2017. Eighteen miles of main were replaced in 2018 and planned for 2019. This was a step up from previously replacing 2-6 miles of main per year. One mile may not seem a very long distance to replace. But each mile represents approximately 12 separate projects; 15 miles required administering about 180 contracts each year.

Protecting the water infrastructure
In the 25 years after the Crypto crisis in 1993, the Milwaukee Water Works invested $508 million in water treatment, water quality monitoring, water mains and pumping facilities, real-time monitoring, customer service, and security to ensure high quality water and water service.

The Milwaukee Water Works owns 14 sizes of mains made primarily of cast iron, ductile iron; larger mains are made of high pressure concrete.
The distribution system includes 2,000 miles of water mains. If laid end to end, the mains would reach from Milwaukee to Seattle. After we treat Lake Michigan water, it flows into large underground clearwells at the water treatment plants that temporarily hold the water before it is pumped into the distribution system. Water mains form an underground network in a grid system for distributing water. The utility also maintains 20,000 hydrants.

The larger diameter water mains, or feeder mains, are in diameters of 20", 24", 30", 36", 42", 48", 54", 60", and 84". They carry water from the three major pumping stations to smaller mains, and to seven booster stations to ensure consistent and adequate water pressure throughout the various elevations in our service area. The next smaller size mains are in diameters of 4", 6", 8", 12", and 16". The pumping and booster stations also pump water into storage facilities such as two elevated storage tanks and four ground level tanks for additional supply during increased water demand periods. The age range of our water mains is 1873 to the present.

We maintain, repair and replace all of the mains, valves, and hydrants in the water distribution systems in Milwaukee, Greenfield, Hales Corners, and St. Francis to ensure continuous delivery of sufficient high-quality water. Scheduled maintenance activities include:

  • inspection and repair of facilities within planned paving projects
  • annual flushing of a selection of mains
  • leak surveys to identify non-surfacing water leaks
  • a hydrant inspection program. We regularly flush the hydrants and test the water quality at each hydrant. Information about each hydrant is stored in a file accessed by a bar code on each hydrant.

Causes of main breaks
Mains are made of iron and are buried in soil which promotes corrosion. The corrosion weakens the structure of the pipes, which over time results in small holes and cracks appearing. As the water leaks through these holes and cracks, the pipe becomes even weaker and this can result in a burst water main. Other causes of main breaks are ground movement (e.g., due to frost penetration), changes in water pressure, electrical corrosion, being struck during excavation by other underground utility work, pressure from heavy traffic or construction, and normal age deterioration.

Most main breaks occur in the most prevalent diameters of pipe, 6" and 8". Because water mains are under great pressure, even a small hole can allow large amounts of water to escape. The average cost of repairing a broken water main is approximately $2,400.00.

Main Breaks usually increase in number during winter months

Winter freeze and thaw cycles cause an increase in broken water mains as the water in the soil under the pavement freezes and thaws, putting pressure on the mains which causes breaks. Water mains are located under the streets about 6-1/2 feet down. In order for the cold to affect them, the frost line must penetrate that deep. Almost half of the breaks in any given year occur in December, January, and February. The biggest impact of a main break in winter is icing conditions from water flooding the street.


The water main repair response

When a main break or water leak in the street is reported, our Control Center dispatches a Field Investigator to assess the situation and determine the appropriate utility response, authorize the call-out of repair crews if needed, and assist in obtaining materials, supplies, maps, and records to expedite repairs. The Investigator determines if there is a water leak, and if so, takes steps to isolate the leak by operating underground valves. The valves are throttled to regulate the water flow and reduce the amount of water flowing while still providing water to customers. Although we don't want to waste water, we try to continue water service to customers as much as possible and minimize shutoffs. If the main break is creating damage that cannot be controlled by throttling the main, the water will be shut off without notice.

"We call before we dig"

The Wisconsin Diggers Hotline law requires the Milwaukee Water Works to notify all other utilities with underground equipment, cables, gas lines, etc., located near the main break. Before our crew is allowed to excavate for repairs, a representative from other underground utilities must assess the situation and provide the location of their facilities to avoid damage during excavation. This also protects our crews working on the site. Waiting for other utilities and final approval can take several hours.

Water main repairs in progress

Once utilities are marked, the crew proceeds to locate the leak. Because water takes the path of least resistance, the place where the water is surfacing does not always correspond to the location of the break. To locate the break and avoid unnecessary excavating, the crew may drill test holes through the pavement. They then push metal probing rods through the holes to make contact with the water main and listen for the leak sound to better pinpoint the location of the escaping water. Once the crew locates the leak, they notify customers in the area of the water shutoff and give them time to draw a temporary supply of water while the crew sets up barricades and digging equipment.

Excavating and repair

The repair crew begins by installing environmental protection measures around the site to reduce the amount of erosion and runoff. Then they dig at the location of the leak. Once excavated, they protect the hole from collapsing. This is essential to protect workers. They remove some of the dirt around the main and replace it with new material, then repair the main. The crew then slowly opens a valve to allow water to flow from a hydrant. This reduces the amount of air trapped in the system and thoroughly flushes the main to ensure high quality water.

Once the repair is complete, the water is turned back on and the hole is filled and covered with blacktop as a temporary patch or restored with permanent pavement by the Department of Public Works Street Maintenance Division. Landscaping repairs for grassy areas in the public way are completed during warm weather months.

Milwaukee Water Works Safe, Abundant Drinking Water

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Customer Service Center

Zeidler Municipal Building
841 N. Broadway, Room 406
Milwaukee, WI 53202
Open Monday - Friday 7:30 a.m. - 5:00 p.m.

Mailing address: P.O. Box 3268, Milwaukee, WI 53201-3268


 (414) 286-2830

24-Hour Control Center  

 (414) 286-3710


 (414) 286-8801


 (414) 286-5452

Email (non-emergency)