FAIRMONT - "I & I" is a notorious abbreviation, well-known in public utilities circles, and potentially becoming more familiar to ordinary citizens.
Standing for inflow and infiltration, I & I can be expensive, creating avoidable treatment costs for cities. When storm water seeps - or gushes, depending on the rainfall - into the sewage system, cities have to treat that water, and that adds up.
"Every community's facing it," Butch Hybbert, Fairmont's wastewater and water treatment supervisor, told the Public Utilities Commission on Tuesday.
For years, Fairmont has worked to reduce I & I by replacing old pipes during reconstruction projects, but the progress is slow and the results have been less than encouraging. Hybbert said the city is still seeing spikes in the amount of water coming into the wastewater plant after rainfalls.
The problem lies in part with private connections to the sewer system. Some residents have sump pumps hooked directly to their sewer lines instead of directing them into storm drains. But even more common are homeowners who still have old clay pipes connecting to the city's sewer system.
Compare Fairmont's I & I with other southern Minnesota cities, and it seems many are in the same leaky boat.
"It is a little tricky to compare apples to apples," said Troy Nemmers, public utilities director.
Fairmont staff were surprised to find no one they contacted monitors their inflow and infiltration and compares it to their water sales - or if they do, they didn't want to share it, Nemmers said.
Making due with information available, staff compared cities' actual winter flow into wastewater plants with actual summer flow. They took into account the July 2010 rainfall and assumed there would be no inflow into the wastewater system during the winter.
"We really sit pretty good overall if you compare rainfall reports to I & I," Nemmers said.
Fairmont's flow into its wastewater plant was 44.93 million gallons in December 2009 and jumped to 84.98 million gallons in July. That puts the amount of water needlessly being treated at an estimated 47 percent.
In comparison, St. James' I & I was estimated at only 39 percent for the same time period, Blue Earth's was at 68 percent, and Winnebago was at 50 percent.
"St. James is the only one doing a lot of work on I & I," Hybbert said.
Fairmont, in his opinion, needs to move to the next step, and that could mean requiring private property owners to upgrade their connections to the sewer line.
"If we want to address the I & I, we've got to look at the whole picture," Hybbert said.
Nemmers, speaking from experience, anticipates homeowners will be less than pleased with the city for tearing into their front yards: "The biggest issue with residents is when we do our restorations."
Further complicating the issue is location. The older connections, where clay pipe is still in place, are not in the newer residential neighborhoods - they're in the areas where residents are less likely to be able to afford the improvements.
"It's a significant cost," Nemmers said.
The average for sliplining a pipe is $100 to $110 per foot.
Some communities have a policy in place to assess homeowners for part of the cost, and others are hard-nosed, requiring residents to upgrade if they want to hook up to the wastewater system, Hybbert said.
A less expensive option might be to take Duluth's approach, and do the work from homeowners' basements rather than outside.
"It's easier to replace concrete and put carpet back down than replace every blade of grass," Hybbert said.
The Public Utilities Commission will continue to study the problem before making recommendations to the City Council.