Elm Grove lateral leaks prove worse than expected
Village will pay for repairs with money from MMSD
An inspection of private laterals in Elm Grove found that more than half have moderate or major leaks, Village Manager Dave DeAngelis said.
A lateral pipe takes water used in the home or business to the sanitary sewer in the street, which eventually ends up at the Milwaukee Metropolitan Sewerage District plant. Cracks and holes in the pipes allow groundwater to leak into the sanitary sewer system, overloading the system and causing backups into basements - especially during heavy rains.
A private engineering company conducted the study earlier this month with funding from the MMSD Private Property Inflow Infiltration Reduction Program, DeAngelis said. Water colored with a nontoxic green dye was pumped into the sewers and a camera pushed into the lateral let engineers see where the excess water was coming from.
Damage found included cracks, collapsed pipes and roots in pipes, he said.
Two areas studied
There were two address map zones with a total of 76 laterals inspected in Elm Grove. Area 1 included some homes from Elmhurst Parkway to the south, west to Blue Ridge Boulevard, north to Walnut Road and east to Woodside Lane.
Fifteen laterals in Area 1 were labeled as having major leaks, and 13 were labeled as having moderate leaks. A major leak is classified as a leak of more than three gallons per minute.
Area 2 included some homes in the 800 block of Grandview Drive, the 800 block of Kurtis Drive and the 800 block of Brinsmere Drive. Of those homes, six had major leaks and seven had moderate leaks.
DeAngelis said the results showed more affected homes than expected.
"These are the two areas where when we have heavy rain, backups occur," he said. "It's a little more than what we were thinking. We were only thinking 30 to 35 percent."
Many laterals in the village were buried when the homes were built and are made of older material.
"A lot of the laterals here are made of clay pipe and have joints every three feet that deteriorate over time," DeAngelis said. "Trees are also a culprit because roots can get in the gaps."
MMSD Public Information Manager Bill Graffin said leaking laterals can overwhelm street pipes.
"These 8-inch sewer pipes can normally handle about 300 gallons per minute. What's being found are homes leaking more than 50 gallons a minute through each lateral," he said of MMSDs overall findings. "Fifty gallons times six to 10 homes will stress the pipes in the street."
Graffin said the overflow causes problems for both homeowners and MMSD. Too much water in the pipes either results in backups or the release of untreated water into local waterways to reduce the pressure.
Affected homeowners will be contacted by the village by mail.
"Residents will receive reports along with a letter explaining the rest of the process," DeAngelis said.
The next step is for the same engineer to develop a repair plan that will be put out to bid. Some of the damaged pipes can be repaired by lining the lateral with a polymer that is catalyzed by warm water, creating a new, smooth surface in the pipe. Others may require relays.
Costs in other municipalities are estimated at $7,000 per lateral. The village will fully cover the repairs to laterals through the MMSD Private Property Inflow Infiltration Reduction Program, which began in 2010 and serves 28 municipalities. The village receives a yearly allowance from MMSD specifically for investigative work and repairs based on work plans required by the MMSD.
"If the work plan falls within the guidelines of taking excess clear water of the system, we will approve reimbursement after the work is done," said Jerome Flogel, MMSD senior project manager.
MMSD doesn't directly pay for 100 percent of all repair costs. That is determined by how each municipality budgets its yearly allowance.
DeAngelis said the village anticipates the cost of the repairs may be more than what is currently available and is awaiting an additional $100,000 allowance for 2013, bringing the grand total to nearly $300,000.
Other municipalities have a cost-share program for homeowners to contribute to the repairs.
Graffin said this program is another method MMSD is using to improve the entire sewer system, which contains more than 3,000 miles of lateral pipes.
"We've invested more than $4 billion over the last three decades improving the regional systems, treatment plans and deep tunnel system, and communities have spent millions of dollars improving their systems, but very little work has been done on private laterals," he said.
Early detection hard
MMSD officials said private lateral leaks are sometimes difficult to detect early because homeowners don't know there is a problem until the backups occur. Further, repairs can't guarantee backups won't occur in the future.
"These improvements are meant to reduce the risk of backups over time," he said. "Every drop of excess water we can keep out of the sanitary sewer, water that isn't supposed to be there, the better off we all are," Graffin said.
MMSD has several videos on its website explaining how laterals work, the private property program and tips on maintaining laterals. Go to BasementConnection.mmsd.com.
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