Water Mains: Replacement and Maintenance
To report a water main break please call our 24-hour Control Center at (414) 286-3710.
Main Breaks December 25, 2017-January 15, 2018
Water Main Replacement Program
Investments in water main replacements is paying off. We're seeing a downward trend in the number of main breaks per year since the 1970s with the fewest in that period in 2017. 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.
We select water mains for replacement when they have reached the end of their useful life. 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 $1.3 million. There is no special assessment or added cost to property taxpayers. The projects are paid for using the utility’s capital improvements budget which is funded with revenues from water rates.
We have a long-range program to replace aging water mains. Fifteen miles of main were completed each year, 2015-2017. This was a step up from previously replacing 2-6 miles of main per year. Each mile represents approximately 12 separate projects; 15 miles requires administering about 180 contracts each year.
Protecting the water infrastructure
Since 1993, the Milwaukee Water Works has 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 Capital Improvements Program prioritizes projects based on results of water-elated research, new technology, and condition assessments of existing systems.
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 form a pipeline long enough to reach from Milwaukee to Seattle. After we purify 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 in the distribution system, 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
A main break is a crack, split, or hole in the pipe from which water escapes. Some of the causes of main breaks are ground movement (e.g., due to frost penetration), changes in water pressure, corrosive soil conditions, electrical corrosion, being struck during excavation by other underground utility work, pressure from heavy traffic or construction, and normal age deterioration.
Almost half of the breaks in any given year occur in December, January, and February. Increased soil pressures, caused by freezing, thawing, and shifting, affect weak spots of a water main, causing breaks.
Most main breaks occur in the most prevalent diameters of pipe, 6" and 8". The MWW repairs an average of 575 main breaks per year (Average 2007-2017). 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 $2,400.00.
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.
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.
"Don't wake me - just fix it"
The MWW repair crew will notify customers affected by the water shutoff by going door-to-door telling them to prepare for a water outage. Customers who do not answer will receive a door hanger on their front door. To avoid disturbing customers, we do 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, 414-286-3710, for information about the status of a repair.
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.