Inflow and Infiltration Point of Sale

What is Inflow and Infiltration?

Inflow and Infiltration (I/I) is the excess flow of clear water into the City's sanitary sewer system.  The City of Moose Lake owns and operates the sanitary sewer collection system and wastewater treatment ponds. Because the sanitary sewer system was not designed to handle this excess clear water, the system and ponds can becomes overloaded during times of high groundwater or heavy rainfall. This limits the capacity of the ponds, can cause basement flooding or bypassing of raw wastewater to local streams and lakes. 

Why is I/I a Problem?

The excess clear water from I/I problems uses sanitary sewer capacity needed for the City wastewater treatment ponds. This results in limiting development opportunities in the area, potential sewer backups and increased maintenance costs for needlessly putting clear water through the wastewater treatment process.  Water that goes down any drain in your house leads to the sanitary sewer system and eventually ends up at the City wastewater treatment ponds, where it is treated before being released back into the environment.  Wastewater from Moose Lake and Windemere Township travels through the City’s sanitary sewer system to the waste water treatment ponds.  The City of Moose Lake also permits any new connections to the sanitary system.  When the ponds are at their capacity, new connections for development can be limited or even denied.  Therefore, the City is investing in local reduction remedies to urge compliance and ultimately increase wastewater pond capacity and operating costs.  Since sanitary sewer rates are based on the number of gallons that flow through the City sanitary sewer system, treating clear water is costly to everyone.  

I and I


The Point of Sale ordinance is intended to help reduce peak sanitary sewer flows caused by Inflow and Infiltration (I/I), or flow of clear water into the sanitary sewer system. The City’s wastewater pond capacity is limited and in order to reduce unnecessary water from entering the ponds, the City of Moose Lake requires a point of sale inspection to identify and reduce I/I to the wastewater collection system. These inspections allow the City to ensure that private properties have no illegal connections to the sanitary sewer system or pipe defects that contribute to excess peak flow discharges.


Those properties connected to the Municipal Sanitary Sewer who do not have a valid certificate of I/I Compliance when one of the following situations occurs:

  • Prior to Sale:   All properties in Moose Lake must be inspected and required to be in compliance before they can be sold. 
  • With Permits: Property owners who apply for sewer connection or disconnection permits will also be subject to an inspection


The application fee is $250 for residential properties and $750 (per building) for commercial or multi-unit buildings.


To comply with Moose Lake’s I/I point of sale MCES directives regarding I/I, the Property Owner shall, at their own expense, inspect, and provide to the city a report of the results of an inspection of, the laterals on their property prepared by a licensed plumber or a qualified and licensed person using closed circuit television (CCTV) inspection or other inspection or test method approved by the City Engineer.  The inspection will determine if roof drains, foundation drains, sump pumps, and other clear water sources are connected to the sanitary sewer system. The goal of this program is to reduce excessive flows that enter the sanitary sewer system. 

Ordinance No. 166: An Ordinance to Establish Certification of Inflow and Infiltration (I&I) Compliance

Inspection Form