Should I get a sewer scope inspection before buying a home?

A sewer scope is a video inspection of the sewer lateral, the underground pipe that runs from the house to the public sewer main or, on a septic property, to the tank. A plumber feeds a small waterproof camera on a flexible cable into a cleanout or another access point and pushes it the length of the line while watching a live screen. The recording becomes part of your due diligence file.

The camera shows things no walk-through or surface inspection can. According to InterNACHI, a sewer scope can reveal blockages, root intrusion, cracks, bellies, and breaks, and it also confirms the pipe material. That material matters. If the camera finds Orangeburg pipe, a tar-and-paper product used decades ago, or aged cast iron that has rusted and scaled shut, you are looking at a line near the end of its service life.

A belly is a low spot where the pipe has sagged and lost its slope, so waste and water pool instead of draining. A crack or offset joint lets in soil, roots, and groundwater. Root intrusion is what happens when tree roots find a joint or fissure and grow inside the pipe, and a fully collapsed section means the line is no longer carrying flow at all. Each of these is something you would otherwise find the hard way, after a backup, once you already own the home.

The scope also gives you a baseline. Even on a sound line, knowing the material and the rough age helps you plan. A clay or cast iron line that looks fine today still tells you what is coming in five or ten years, so you can budget for it instead of being caught off guard. A new owner who has watched the video knows exactly what is under the yard.

This is the point most buyers miss. A general home inspection is broad but it stops at the surface of the plumbing. InterNACHI's Residential Standards of Practice, the rulebook many home inspectors follow, defines what a routine inspection must cover, and a sewer scope is not on that list.

The Standards of Practice state plainly: "The inspector is not required to inspect... any system that is not readily accessible." A buried sewer lateral is the textbook example of a system that is not readily accessible. A standard inspection runs the faucets, flushes the toilets, and checks that fixtures drain, but it does not send a camera underground. The Standards also exclude underground or concealed piping and septic systems from the routine scope of work.

That is why a sewer scope is an ancillary, or add-on, service. You order and pay for it separately, usually as a specialty inspection by a plumber or a dedicated sewer-scope inspector. It is not bundled into the home inspector's flat fee, and an inspector who follows the Standards is not failing you by leaving it out. The responsibility to ask for it sits with you, the buyer. If you assume the home inspection "covered the plumbing," you can close on a house with a failing line and never know until it is your problem. For the full picture of what the routine inspection does and does not cover, see our guide on what a plumbing inspection covers when buying a home.

The lateral is your pipe. In Phoenix and most metro cities, once you close, the homeowner owns and pays to repair the building sewer from the house to the public connection. The buried line you never see becomes your financial responsibility the day the deed transfers. We cover the exact split between owner and city in who is responsible for the sewer line in Phoenix, but the short version is that the section on your property is on you.

A sewer repair is one of the most expensive plumbing jobs a homeowner can face. Reaching a buried line means excavating a yard, a driveway, or even cutting through a slab, and a full lateral replacement can run into many thousands of dollars. A clogged or broken line also causes the kind of damage insurance often will not pay for. Sewer backups are not covered under a typical homeowners insurance policy unless you have bought a separate backup endorsement, so a surprise failure can hit you twice, once for the pipe and again for the cleanup.

The numbers around sewer failures are not small. The EPA estimates there are tens of thousands of sanitary sewer overflows every year, and blockages, often from roots and grease, are a leading cause. Catching a problem before you buy turns it into a negotiation point. You can ask the seller to repair the line, credit you for the work, or drop the price. After closing, you have lost all of that bargaining power and own the bill outright. A few hundred dollars spent before the deal closes can save you many thousands after it.

Phoenix has features that make a sewer scope especially worth it. Many of the valley's established neighborhoods were built decades ago, so their laterals are old cast iron or clay that has had years to crack and corrode. Per InterNACHI's life-expectancy chart, cast iron waste pipe runs about 60 years below ground, which puts a lot of pre-1970s Phoenix homes at or past the end of that window. Mature desert trees and large ornamentals send aggressive roots toward the steady moisture and nutrients inside a sewer line, a problem we detail in signs of tree roots in your sewer line. The valley's many slab-on-grade homes raise the stakes further, since a line that runs under a concrete slab is far costlier to reach and repair.

The inspection itself is quick and clean. The plumber locates a cleanout or pulls a toilet to access the line, feeds the camera through, and records the run while narrating what the screen shows. A clean result means the pipe is intact, the slope is good, water flows away freely, and the material has useful life left. That is real peace of mind on a six-figure purchase.

A problem result flags specific defects with footage you can hand to a contractor for a repair estimate. Roots can sometimes be cleared and the line relined; a collapsed or bellied section may need replacement; failing Orangeburg or cast iron usually means budgeting for a new lateral. Ask the inspector to mark roughly how far down the line each defect sits, since that distance shapes the repair plan and the cost. Either way you make the decision with facts instead of guesses, and you do it while you still have room to negotiate. Running fixtures and checking for hidden leaks is good practice anyway, since the EPA notes the average home wastes more than 9,300 gallons a year to leaks, but only a camera shows the buried line.

Get the sewer scope. On a home built before the 1980s, on any lot with mature trees, or on a slab-on-grade Phoenix property, treat it as a standard part of due diligence rather than an optional extra. The inspection is inexpensive next to the line it protects, and it is the only way to see the one expensive plumbing system that a routine home inspection leaves out.

Schedule it during your inspection window, while you can still act on what it finds. Ask for the recorded video and a written summary, and make sure the inspector confirms the pipe material and notes any roots, cracks, or bellies. If the scope comes back clean, you buy with confidence. If it does not, you have hard evidence to renegotiate or walk away before the lateral, and its repair bill, become yours.