Buying a home in Chicago is exciting, and a little nerve-wracking. You’ve fallen in love with the place, your offer’s been accepted, and now you’ve got a narrow window to find out whether anything’s seriously wrong before you close.

Most buyers focus on the obvious: the roof, the furnace, the foundation. But some of the most expensive surprises in a Chicago home aren’t visible at all. They’re underground.

A sewer line problem found after closing is no longer the seller’s issue. It’s yours. And in older Chicago neighborhoods, where many homes still have original clay or cast iron pipes, sewer issues are more common than most buyers realize.

Here’s what to watch for during your home inspection, and why it’s a good idea to also get a plumbing or sewer inspection, as well.

Why Sewer Issues Get Missed

A standard home inspection is a visual check. Inspectors look at what they can see: fixtures, exposed pipes, water pressure, drain flow. They’re trained generalists, not sewer specialists, and they don’t have the tools to look inside your underground pipes.

That’s a problem because the most expensive sewer issues — collapsed lines, root intrusion, bellied pipes — happen inside the line, several feet below the yard. A house can show zero symptoms during a 30-minute walkthrough and still have a $15,000 problem waiting underground.

This is especially true in Chicago, where many homes were built over 100 years ago. If a home was built before the 1980s, there’s a real chance the sewer line is original, and original means clay or cast iron, both of which have a finite lifespan.

Common Sewer & Drain Issues in Chicago Homes

Here are the issues that come up most often when we inspect sewer lines for buyers:

• Tree root intrusion: Roots are drawn to the moisture inside sewer pipes. They find their way in through small cracks or pipe joints, then grow until they partially or fully block the line. Common in any neighborhood with mature trees, which is most of Chicago.
• Cracked or collapsed clay pipes: Clay was the standard material in Chicago for decades. It’s durable but brittle, and after 60 to 100 years in the ground, it cracks, shifts, and eventually fails.
• Corroded cast iron: Cast iron pipes rust from the inside out. Over time, the interior surface gets rough and narrowed, which slows drainage and traps debris. Eventually the pipe walls thin and develop holes.
• Bellied pipes: A “belly” is a low spot where the pipe has sagged, usually because of soil shifting. Waste collects in the dip instead of flowing through, which leads to recurring clogs that no amount of rodding (sometimes called “snaking”) can permanently fix.
• Missing or failed backwater valve: Many older Chicago homes don’t have a backwater valve installed. Without one, a surge in the city main during heavy rain can send sewage back into the basement.
• Hidden previous repairs: Sometimes, a previous owner has done a partial or DIY repair on the line. These often hold up for a while, then fail in ways that aren’t obvious from the surface.

Home Inspection Plumbing Checklist

Use this checklist alongside your standard inspection to make sure nothing gets missed:

• Run every faucet and flush every toilet. Listen for gurgling, watch for slow drainage, and check for any sewer smell.
• Look at the basement floor drain. Stains, residue, or watermarks around it can signal past backups the seller may not have disclosed.
• Check for a backwater valve. Ask the inspector to identify whether one exists. If you can’t confirm there is one, assume there isn’t.
• Inspect the cleanout. A cleanout is the access point to the main sewer line — usually a capped pipe in the basement or yard. If there isn’t one, that’s worth noting.
• Examine the basement walls and floor for water staining. Efflorescence (white chalky residue) or visible cracks can suggest past flooding.
• Ask about the sump pump. When was it last replaced? Is there a battery backup? Has it run recently?
• Check downspout connections. Look at where downspouts terminate and where the runoff flows (it should be directed away from the property).
• Get a sewer camera inspection. This is the only way to actually see inside the line. More on this below.
• Ask the seller for any past plumbing records. Recent rodding, repairs, or backups should be disclosed, but be sure to ask directly if no details have been provided.

Benefits of a Camera Inspection

A sewer camera inspection, sometimes called a sewer scope, is the single most useful diagnostic tool available to homebuyers. A small, waterproof camera is fed through the sewer line from a cleanout or access point, sending live video back to a screen so the technician (and you, if you’re there) can see exactly what’s inside the pipe.

Here’s what makes it worth the cost:

• You see real conditions, not guesses. Instead of inferring from drainage speed or basement stains, you get visual proof of what’s actually happening underground.
• You catch the expensive stuff early. Cracked pipes, root intrusion, bellies, and corrosion all show up clearly on camera. Catching them before closing means you can negotiate repairs into the deal, or walk away from a bad one.
• You get leverage in negotiations. A documented sewer problem is hard for a seller to dispute. Camera footage gives you concrete evidence to request a price reduction, repair credit, or seller-completed repair before closing.
• You start ownership with a baseline. Even if the line is in good shape, you’ve got a record of its condition on day one. That’s useful for spotting changes down the road.
• You protect yourself from a five-figure surprise. Sewer line replacement in Chicago can run anywhere from $5,000 to $25,000+ depending on the length, depth, and whether excavation requires tearing up the street. A few hundred dollars upfront is cheap insurance.

Before You Close, Take a Look Underground

If you’re buying a home in Chicago, especially one built before 1980, a sewer camera inspection is one of the smartest things you can add to your due diligence. It takes about an hour, costs a fraction of what you’d spend on a sewer repair, and tells you exactly what you’re buying.

Madden Sewer & Drain has been doing camera inspections for Chicago homebuyers for decades. We’re family-owned, licensed, and bonded, with a 4.9-star rating across 300+ Google reviews. We’ll show you what’s in the line, explain what it means, and provide an estimate for any recommended repairs.

Call 773-588-7534 to schedule a new home sewer inspection. We’ll get you on the calendar before your inspection contingency runs out.