Stormwater in sewers threatens region's growth capacity

Metro Council adopts surcharge program to reduce clear water in the regional wastewater treatment system

ST. PAUL—(Feb. 8, 2006)—They are the skeleton of development in the Twin Cities urban area. Thousands of miles of sewer pipe and a network of treatment facilities that preserve the environment and protect public health.

It’s a system that works better than almost any other in the country. But it has a major detractor in the form of -- clear water! Today, the Metropolitan Council approved a five-year surcharge program to remedy, in partnership with metro-area communities, the issue of too much clear water in sanitary sewer pipes.

The Metropolitan Council operates the region’s wastewater collection and treatment system, treating almost 300 million gallons of wastewater each day at eight regional treatment plants. It’s the Metro Plant in St. Paul, however, that does the heavy lifting, taking on two-thirds of the workload.

Add a heavy rainstorm, and the big plant can experience triple the usual load--700 million gallons a day or more. And therein lies part of the problem.

Stormwater, for example, that finds its way to the treatment system through basement sump pumps and foundation drains that are illegally connected to sanitary sewers. It’s called “inflow” and it uses up capacity and can cause sewer backups and overflows into lakes and rivers. In addition, customers, meaning sewered homes and businesses, pay the cost of processing water that doesn’t need to be conveyed and treated.

Clear water can also find its way into sewer pipes through cracks in the pipe and leaky joints. That’s called “infiltration.” Inflow and infiltration--in the business, it’s known as “I-and-I,” and it has implications for growth.

“We need to reserve sewer capacity for new homes and businesses in our growing region,” said Council Chair Peter Bell. “We simply can’t afford to build enough sewer capacity to accommodate the excess flow from clear water, so we need to fix the problem at its source.”

The Council did, in fact, contemplate the option of enlarging the regional wastewater system to handle I/I at a hefty cost of at least $900 million. The more palatable alternative, however, is estimated to cost $150 million and relies on communities to fix leaky local pipes and work with homeowners to do away with illegal connections to the sanitary sewer, something the City of Forest Lake has done with significant success.

Forest Lake, in 2004, committed $120,000 to a two-year inspection program, requiring homes and businesses with sump or drainage connections to the sanitary system to eliminate those connections. The city apparently achieved its I/I reduction goals, saving the region $6 million in potential costs associated with adding more capacity to accommodate excessive flow.

The Council has identified 50 to 60 communities contributing excess I/I to the system. The Council’s program serves as an incentive for these communities to come up with a plan to reduce their I/I, or beginning in 2007, pay a surcharge that would fund I/I reduction programs.

Communities may reduce their total surcharges by demonstrating that they can solve their I/I problems at less cost than the Council estimated. Communities can also lessen or eliminate their surcharges by committing local funds toward reducing I/I.

Beginning in 2013, the Council will up the ante and assess a more costly “demand charge” on communities that don’t meet their I/I goals and use those funds to help pay the costs of expanding sewer infrastructure. At that point, the Council will also consider restricting future sewer expansions in communities where excessive I/I limits sewer capacity.

“The objective is to never get to that point,” said Bell. “But rather to work collaboratively with communities in the meantime to reduce the I/I in the wastewater system.”

The surcharge was recommended by a Council-appointed task force made up of local government representatives. The group was charged with taking a look at the problem and proposing strategies to solve it. Their recommendations were incorporated into the Council’s 2030 Water Resources Management Policy Plan, adopted early in 2005. Council staff then developed the surcharge program with public input, including public meetings attended by more than 100 community representatives.

“It’s a proactive management program that will help protect the integrity of the wastewater treatment system and avoid future capacity issues,” said Jason Willett, Environmental Services Finance Director. “It places the cost of fixing the problem on those who are experiencing it, rather than the entire region, and helps keep the overall cost to a minimum.”

“It’s a balanced approach,” said Bell. “We want to be flexible, but at the same time address the issues we face in a timely manner.”

The Twin Cities region offers some of the most competitive rates in the country for sanitary sewer service, with the average household paying about $15 a month. For information on how that rate compares with other household services, and how regional rates compare with other sanitary districts of similar size, visit the Council’s web site at www.metrocouncil.org/environment/RatesBilling/Competitiveness.htm.

See an overview of the I/I issue at www.metrocouncil.org/planning/environment/inflow_infiltration.htm.

NEW See the I/I home page with the latest information on the program at www.metrocouncil.org/environment/ProjectTeams/I-I-Home.htm

The Metropolitan Council is the regional planning organization for the seven-county metro area. It runs the regional bus and light-rail system, collects and treats wastewater and coordinates water resources preservation, plans regional parks and administers funds that provide housing opportunities for low- and moderate-income individuals and families. The 17-member Metropolitan Council is appointed by and serves at the pleasure of the governor.

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