By Adam Marvel Blog Posts sewer pipes October 28, 2026

Inflow & Infiltration Services: What Are They?

Inflow & Infiltration services find and fix the places where clean groundwater and stormwater get into a property’s sanitary sewer line. Across the Twin Cities, a growing number of communities require a passing I&I inspection before a home or business can be sold. Each city sets its own rules for inspections, certificates, and repair deadlines. This guide explains what I&I is, what the work involves, and how the requirements differ across ten local cities.

What Is Inflow & Infiltration?

Every property has two separate drainage paths. The sanitary sewer carries wastewater from toilets, sinks, and showers to a treatment plant. Rain and groundwater are supposed to go into your yard or the storm sewer instead. I&I is what happens when that clear water ends up in the sanitary line anyway.

Inspectors usually split the problem into two categories:

Inflow is water entering through a direct connection, such as a sump pump hose, roof downspout, or foundation drain tied into the sanitary sewer.
Infiltration is quieter and harder to spot, because groundwater seeps in through cracks, separated joints, and gaps that tree roots have pried open.

Minnesota takes this seriously enough that state law allows cities to create I&I prevention programs and offer loans or grants to property owners who need repairs.

Why Twin Cities Communities Care So Much About Clear Water

Wastewater from most of the metro is treated by the Metropolitan Council. When clear water fills the pipes, cities pay to treat water that never needed treatment. That cost eventually shows up on residents’ sewer bills.

Heavy rain makes the problem worse. Extra water can overload the system and push sewage back into basements. The Metropolitan Council’s I&I program points out that more than half of the clear water in the regional system comes from private homes and businesses.

That’s why so many cities now focus on the sewer lateral, the pipe running from your building to the city main. In most of these communities, the property owner owns the lateral, so repairs to it are the owner’s responsibility.

What Inflow & Infiltration Services Include

A good I&I service starts with clear information and ends with a verified fix. Our Empowerment Guarantee is built around showing you exactly what’s happening underground so you can make a confident, informed decision.

A sewer camera inspection of the full lateral, recorded so your city can review the video
Checking where the sump pump discharges, since it should exit outdoors or into the storm sewer
Looking for roof drains or foundation drains that are tied into the sanitary line
Locating cracks, root intrusion, sags, and separated joints, along with the depth and position of each defect
Repairs that range from a targeted spot fix to trenchless pipe lining of the entire line
Post-repair video and documentation to help you secure a Certificate of I&I Compliance

How I&I Rules Differ From City to City

There’s no single statewide requirement. The Minnesota Pollution Control Agency notes that state law does not require a lateral inspection during a real estate sale. Each city decides for itself whether to add one.

When you compare local programs, a few details tend to vary the most:

Who performs the inspection, either a city crew or a contractor you hire
What triggers it, such as listing a home, closing a sale, or a nearby road project
How long a passing certificate stays valid
Repair deadlines and whether grants or reimbursements are available

Here’s how the cities we serve for I&I work handle it. Rules change over time, so confirm current requirements with your city before you list a property.

Golden Valley

Golden Valley was the first community in the region to adopt a sewer point-of-sale program, back in 2007. Any property without a Certificate of I/I Compliance must be inspected before it can be advertised for sale.

Sales aren’t the only trigger. An inspection is also required when an owner applies for a plumbing permit over $10,000, a variance, or a minor subdivision. Repairs should be finished within 180 days, and failing to get a certificate can bring monthly utility charges of $500 for homes and $1,000 for non-residential properties. Our Golden Valley Inflow & Infiltration page walks through local inspection and repair options.

West St. Paul

West St. Paul requires an I&I inspection when a property is sold, and the city offers that inspection free through a contractor working on its behalf. A compliant property receives a letter that’s good for 10 years.

Properties that don’t pass get a correction notice. Once repairs are done, owners can submit the paid invoice for a 15% reimbursement. Lining or replacing the entire line exempts it from further city inspections for 25 years, while a spot repair carries a 10-year window. Learn more about West St. Paul Inflow & Infiltration repairs.

St. Anthony Village

Two separate checks are required in St. Anthony Village before a property is advertised or sold: a sump pump inspection and a sewer line inspection video. Sales of individual condominiums are exempt.

What sets this city apart is the three-year certificate, much shorter than most nearby communities. If you plan to sell within a few years, timing your inspection carefully matters here. Our St. Anthony Village Inflow & Infiltration team can help you plan around that window.

Mounds View

Mounds View handles I&I through its Water Preservation Program, known as H2OPP, under Ordinance 967. At the sale or transfer of a property, the owner must have the lateral televised and repaired if needed. Owners hire the televising company themselves.

Passing properties earn a certificate valid for 20 years, the longest on this list. Infiltration problems have to be repaired before the sale, and the city has offered zero-interest loans for inspection and repair costs. Visit our Mounds View Inflow & Infiltration page for details.

Orono

Under City Code Section 14-190, an Orono property served by municipal sewer can’t change ownership without a certificate of I&I compliance. The city can perform the inspection, or the owner can hire a licensed plumber to check the sump pump, sewer lateral, and groundwater drainage system.

A passing certificate lasts 10 years. When problems turn up, Orono asks for repairs within 90 days of the first inspection, which is a much tighter timeline than Golden Valley’s. Our Orono Inflow & Infiltration services are built to help sellers move quickly.

Tonka Bay

Since July 2020, Tonka Bay has required a certificate before any property is sold or changes ownership. Sellers hire a professional to televise the line from the home to the road, then submit the video with an application and a $150 fee per lateral.

The Public Works Superintendent reviews the footage against Section 827 of city code, watching for breaks, cracks, sags, and leaks. A clear, complete video makes that review go smoothly, and our Tonka Bay Inflow & Infiltration crew records every inspection with the city in mind.

Deephaven

Deephaven tied its I&I efforts to road work first. In 2023, the city clarified that property owners own their sewer laterals and must inspect and repair them when a road project is approved for the street in front of their property.

City leaders reviewed a point-of-sale approach in 2025. If you’re selling or your street is on the road project schedule, check with the city about current requirements. Our Deephaven Inflow & Infiltration page explains how we help with both situations.

Excelsior

Excelsior’s I&I efforts focus on helping owners pay for repairs. The city takes part in the Metropolitan Council’s private property I&I grant program, which can cover lateral repair or replacement. Inspection and cleaning costs may also qualify when they lead to a repair.

Sewer repairs in Excelsior also require a city sewer and water repair permit. You can find out how we handle permitting and grant paperwork on our Excelsior Inflow & Infiltration page.

North St. Paul

North St. Paul offers a private property I&I grant worth 50% of eligible costs, up to $5,000. Homeowners who meet income criteria can qualify for up to $10,000.

Eligible work includes lateral repairs or replacement, foundation drain disconnections, new sump pumps, and inspection and cleaning. The current round requires work to be completed by December 31, 2026, or until funds run out, so it’s worth acting soon. Our North St. Paul Inflow & Infiltration team can provide the contractor quote you’ll need to apply.

Eagan

Eagan is one of many metro communities the Metropolitan Council lists as affected by inflow and infiltration. Ask the city whether any inspection applies to your sale or remodel before you set a closing date.

Even without a requirement, a camera inspection before buying or selling protects everyone involved. Buyers learn what they’re getting, and sellers avoid surprises late in the process. Our Eagan Inflow & Infiltration services are a smart first step either way.

Certificate Lengths at a Glance

How long a passing result lasts can shape when you schedule your inspection. Here’s a quick comparison:

Mounds View: 20 years
West St. Paul: 10 years, or 25 years after a full-length lining or replacement
Orono: 10 years
St. Anthony Village: 3 years from the inspection date
Golden Valley: the certificate stays with the property, though a sump pump re-check is needed if it’s more than a year old at the time of sale
Tonka Bay: a certificate is required before closing on any sale

What Business Owners Should Know

I&I rules apply to commercial properties too. Golden Valley inspects both homes and businesses, and its monthly charge for noncompliance is twice as high for non-residential properties.

Commercial buildings bring their own challenges, so plan ahead:

Flat roofs often have internal drains, and those are a common source of inflow.
Older buildings may have long laterals with several joints that can separate over time.
Budget for the inspection and possible repairs before the property goes on the market.
A recorded inspection video gives buyers and lenders confidence during negotiations.

How to Prepare for an I&I Inspection

A little preparation keeps your inspection on schedule. Before the crew arrives, run through this list:

Make sure the main sewer cleanout is accessible and not buried behind storage.
Keep the water on, because the inspection can’t be completed without it.
Follow your sump pump hose outside and confirm it isn’t draining into a floor drain or laundry tub.
Look for downspouts that disappear into the ground near your foundation.
Expect the line may need cleaning first if roots are blocking the camera.
Schedule early, since repair windows can be as short as 90 days.

Common Fixes After a Failed Inspection

A correction notice doesn’t automatically mean a torn-up yard. Many I&I problems have simple, targeted solutions, and we provide upfront pricing before any work begins.

Rerouting a sump pump so it discharges outdoors instead of into the sanitary sewer
Disconnecting roof leaders or foundation drains that were tied into the line
A spot repair when the camera shows damage limited to one section
Trenchless lining of the full lateral, which seals cracks and joints without digging a long trench

Full lining can pay off in more ways than one. In West St. Paul, for example, it exempts the line from further city inspections for 25 years.

We Offer I&I Services In The Following Locations

Marvel Sewer & Drain provides camera inspections, compliance documentation, and repairs for property owners throughout these communities. Choose your city to see local details:

Get Your Sewer Line Ready Before You List

An I&I requirement shouldn’t derail your sale or your budget. As a local, family-owned company, we treat every customer the way we’d want to be treated, with honest answers and upfront pricing. Our team will inspect your line, explain the video in plain language, and help you choose the repair that fits your situation.

Call 763-335-1764 to talk with our team, or reach out through our contact page to schedule your inspection. You can also see what your neighbors say about working with Marvel Sewer & Drain before you book.

What is the difference between inflow and infiltration?

Inflow is clear water that enters the sanitary sewer through a direct connection, such as a sump pump, downspout, or foundation drain. Infiltration is groundwater that seeps into the pipe through cracks, loose joints, or root damage. Most I&I inspections check for both.

Who is responsible for repairing the sewer lateral?

In most Twin Cities communities, the property owner owns the lateral from the building to the city main. That means the owner pays for inspection and repairs. Some cities offer grants or reimbursements to help with the cost.

Which cities require an I&I inspection before selling a home?

Golden Valley, West St. Paul, St. Anthony Village, Mounds View, Orono, and Tonka Bay all require an inspection or certificate tied to a sale. Deephaven requires lateral inspections during road projects. Check with your city before listing, since requirements can change.

How long is an I&I certificate of compliance valid?

It depends on the city. Mounds View certificates last 20 years, Orono and West St. Paul certificates last 10 years, and St. Anthony Village certificates last only three years from the inspection date.

What happens if my property fails an I&I inspection?

You’ll typically receive a correction notice listing the problems that need repair. Deadlines vary, from 90 days in Orono to 180 days in Golden Valley. Once repairs are complete, a follow-up video or inspection confirms compliance so the certificate can be issued.

Can trenchless pipe lining fix an I&I problem?

Yes, in many cases. Lining creates a new, sealed pipe wall inside the old lateral, which stops groundwater from seeping through cracks and joints. A camera inspection first shows whether your line is a good candidate.

Are there grants to help pay for I&I repairs?

Several cities pass along Metropolitan Council grant funds to property owners. North St. Paul currently offers up to $5,000, or up to $10,000 for income-qualified homeowners, and West St. Paul reimburses 15% of paid repair invoices. Funding is limited and often runs out, so it helps to apply early.

Should I get a sewer inspection if my city doesn’t require one?

It’s a smart move, especially for older homes. A camera inspection shows buyers and sellers the true condition of the line before closing. Call 763-335-1764 to schedule one with Marvel Sewer & Drain.

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