The most expensive pipe you own is the one you’ve never seen

Malaki Dohm

Most St. Paul homeowners can tell you where their water heater is. Almost none can tell you where their sewer lateral runs, and it’s the single most expensive piece of plumbing they own.
Here’s the part that catches people off guard. In Saint Paul, a property owner is responsible for maintaining and repairing their private sewer service from the property being served to where it connects to the city sewer mainline. Not to the sidewalk. Not to the curb. To the main, which usually sits under the middle of the street.

That means the pipe running beneath your boulevard, under the curb, and out under the pavement is yours to fix. Most people learn this on the worst possible day.

Why roots go where they go
Tree roots are not breaking into your sewer line. They’re being invited.

A sewer lateral carries warm water and nutrients. In a Minnesota winter, that pipe is one of the warmest, wettest things underground. Roots grow toward moisture and warmth, and they find their way in through joints and hairline cracks, openings far too small for you to ever notice.
Once inside, a root doesn’t plug the line. It fans out into a mesh and starts catching things: grease, wipes, paper. The blockage builds over months or years. That’s why the failure feels sudden even though it wasn’t.

This is a particularly St. Paul problem. Much of our housing stock predates 1940, and those homes were plumbed with vitrified clay pipe laid in short sections with mortared joints. Clay is durable – some of it has been in the ground a century – but every joint is a seam, and every seam is a door. Pair that with the mature boulevard elms, maples, and silver maples that make these neighborhoods what they are, and you have a slow-motion collision between two things the city loves.

The warnings you’ll actually get
Root intrusion rarely announces itself. It mutters for a long time first:

A basement floor drain that gurgles when the washing machine empties. A toilet that bubbles when you run the tub. Multiple drains slowing at the same time not one sink, but the whole house trending sluggish. A lower-level fixture that backs up while the upstairs runs fine. A patch of unusually green grass over the lateral’s path.

Any one of these on its own may be nothing. Two or three together usually means the problem is downstream of your house, not in it.

Finding out for certain
The only way to know is a camera inspection. A licensed plumber runs a scope down the line and you watch the footage. Roots are unmistakable on video, a white tangle where there should be an open pipe.

If you’re buying a house built before 1940, this is worth doing before you close. A few hundred dollars for an inspection against a repair that runs into five figures is not a close call.
If roots are found, options range from mechanical cutting and hydro jetting to trenchless lining or full excavation, depending on the condition of the pipe. Cutting buys time; it doesn’t fix the crack that let the roots in.

Paying for it
This is where St. Paul homeowners have more options than they realize.

The city runs a sewer assessment program, a low interest loan that spreads the repair cost over a 20-year period, and most property owners are eligible. It’s assessed against the property rather than requiring cash up front, which for a lot of households is the difference between fixing it and living with it. There is also a deferred emergency loan program available to low income households.

There’s also a Metropolitan Council grant that covers a share of lateral repair costs, but a caution for anyone reading this in October: all 2026 grant funds have been allocated and no more funding is available this year. The program has run annually and is first-come, first-served, so if a repair can wait, it’s worth watching stpaul.gov early in the year rather than discovering the fund empty after the fact.

What to do this fall
Frozen ground makes excavation harder and more expensive. If your drains have been muttering at you all summer, the window to look into it cheaply is closing.

You don’t need to dig anything up to start. Note which drains are slow and when. If more than one is acting up, get a camera down the line before the ground hardens. Finding out in October that you have a problem is inconvenient. Finding out in February, with sewage in the basement, is a different situation entirely.

The pipe has been down there for a hundred years. It can wait a few more months, but only if you know what shape it’s in.

Malaki Dohm has lived in St. Paul for nine years and currently lives in Merriam Park. He is a plumbing apprentice and the founder of The Plumbing Pipeline (ThePlumbingPipeline.com), where St. Paul homeowners can describe a plumbing problem and get a free, no-obligation response.