Establish an on-going budget and program for decreasing inflow and infiltration into sewer lines and losses in drinking water systems.
Best Practice of this action
Rating Guideline
 |
Create a program backed by ordinance for inspecting household/business gutters, foundation drains, sump pump connections, drain tile, lateral service lines, and/or inspections of city-owned sewer lines; report types of water system preventive maintenance; report drinking water observation well data to show a trend of source water levels (falling, stable, or rising). Report an adopted wellhead protection plan under BPA 6.3. |
 |
Make sewer inspections mandatory at the time of property transfers, street reconstructions; require repairs or provide incentives such as 50% reimbursement to property owners to make repairs or enact utility bill surcharges for owners who are non-compliant with I&I standards; report water system leak detection and water meter calibration, replacement and automation. |
 |
Report outcomes from I&I and water loss programs, such as miles clay pipes relined, # of disconnects, % clearwater reduction, GPD removed, water supply leaks (unaccounted/non-revenue water loss; should be under 5%), money saved at the wastewater treatment plant, capital costs avoided by being able to defer capacity additions. |
Resources
Excess groundwater and stormwater entering sanitary sewer collection systems from private sources through breaks, defective joints, tree root intrusion, cross connections, or porous walls is a common problem in Minnesota communities. This happens in two ways:
- Inflow is extraneous/clear water entering a sanitary sewer system by direct connection from roof drains, basement sump pumps, street manhole covers, etc.
- Infiltration is water entering a sanitary sewer system through joints and cracks in sewer lines from groundwater.
- I/I is the total quantity of water from both inflow and infiltration without distinguishing the source.
Toolkits & Tracking:
- See the League of Minnesota Cities' Sewer Toolkit: A Guide for Maintenance Policies and Procedures
- The Capacity, Management, Operation, and Maintenance Program Self Assessment Checklist (EPA) “is a flexible, dynamic framework for municipalities to identify and incorporate widely-accepted wastewater industry practices to: Better manage, operate, and maintain collection systems, Investigate capacity constrained areas of the collection system, and Respond to sanitary sewer overflow (SSO) events.” (Find the LMC model form for a Preventative Maintenance Checklist too).
- For cities in the Twin Cities, the Metropolitan Council has an inflow/infiltration Fact Sheet and resources for cities and offers a customer portal for viewing I/I program-related information.
- The American Water Works Association's free Water Audit Software and manual provides the best management practice tools and guidance water utilities need to efficiently manage their supplies.
- Water utilities report water conservation efforts and outcomes through the Water Conservation Reporting System as part of their annual report to MN DNR's MPARS (MN Permitting and Reporting System).
- Another powerful free tool is the Alliance for Water Efficiency's Water Conservation Tracking [Cost/Benefit] Tool that can evaluate the water savings, costs, and benefits of conservation programs for a specific water utility. It includes a library of pre-defined conservation activities from which users can build conservation programs.
- The Case for Fixing the Leaks: Protecting people and saving water while supporting economic growth in the Great Lakes region (Center for Neighborhood Technology, 2013)
Policies & Ordinances:
- The League of Minnesota Cities 2019 inflow and infiltration model ordinance prohibits the discharge of clean water into the sanitary sewer system from sump pump connections, defective plumbing, and defective sewer service laterals. The ordinance also allows cities to develop an inspection program (citywide or at point of sale only), require corrections by property owners, and assess penalties for violations.
- The Minnesota Rural Water Association provides assistance and resources, including sample ordinances.
Order Number
3