Cast iron sewer lines in Richardson homes

If you own a home on the older side of Richardson, or you are about to make an offer on one, there is a question worth settling early: what is the sewer line made of, and what shape is it in? It is not a glamorous question. It is also one of the few remaining items in a North Texas transaction that can move five figures after everyone thought the numbers were settled.

The good news is that this is a knowable thing. You can find out for a few hundred dollars, well before it becomes a negotiation. What follows is how the timing, the paperwork, and the money actually work here.

Richardson's Age Is Why This Comes Up Here and Not Everywhere

Richardson grew up in the postwar decades, and the housing stock still reflects it. The Census Bureau's 2020–2024 American Community Survey puts the median year built for the city at 1986, with 44.0% of the roughly 47,960 housing units built before 1980 and 54.7% built before 1990.

The citywide number hides the part that matters. Broken out by ZIP code area, the split is dramatic:

Those are Census ZIP Code Tabulation Areas, which approximate but do not exactly match postal ZIP boundaries. Treat them as a strong signal about a neighborhood, not a verdict on a specific address. The only way to know what is under one particular house is to look.

Two things age the pipe faster here than the calendar suggests. Cast iron corrodes from the inside out, so a line can look sound at the cleanout and be badly scaled forty feet in. And North Texas sits on expansive clay that swells and shrinks with the seasons, which is the same soil behavior that drives so much of the foundation conversation in North Texas. Soil movement pulls at joints. Rigid pipe with rigid joints is not built to absorb that indefinitely.

It is also worth knowing where the city's responsibility ends. The City of Richardson's published policy is that the customer or property owner maintains the house lateral between the main and the building. The city offers a program in which Water Utilities will install a two-way cleanout at or near the property line for a fee paid in advance; once that cleanout exists, city staff maintain the section between the cleanout and the main at no cost, while the homeowner remains responsible for everything between the cleanout and the house. The department's number for stoppages is 972-744-4111. Confirm current fees and program status with the city before you rely on any of it.

A Standard Home Inspection Will Not Look Inside the Line

This is where buyers and sellers most often get surprised, and it is worth being precise about, because the rules are published and unambiguous. The Texas Real Estate Commission's Standards of Practice for real estate inspectors, in the version effective February 1, 2022, set out both what an inspector must do and what an inspector is not required to do.

On the required side, an inspector must report the "visible material used for water supply lines and drain lines" (22 TAC 535.231(a)(1)(A)(iv)), report the presence of active leaks, and report deficiencies in "fixture drain performance" (535.231(a)(1)(B)(vi)(V)). That means if cast iron is visible where the line leaves the slab, or in an attic or crawl space, you should see it noted.

On the other side of the ledger, the inspector is not required to inspect "anything buried, hidden, latent, or concealed" (535.227(d)(1)(D)), and is not required to inspect "for sewer clean-outs" (535.231(a)(2)(D)(iv)). Most decisive of all, the standards state that an inspection does not require the use of specialized equipment, including "cameras or other tools used to inspect the interior of a drain or sewer line" (535.227(a)(3)(C)(i)(VII)).

Read plainly: a complete, competent, fully compliant Texas home inspection can miss a failing cast iron sewer line entirely, and the inspector has done nothing wrong. That is not a loophole. It is the scope the rule defines.

Two useful corollaries. First, the standards expressly do not prohibit an inspector from doing more than the minimum, provided the inspector has the competency (535.227(a)(4)) — so some inspectors do offer sewer scoping, and it is worth asking. Second, TREC has stated that only a licensed plumber may perform a hydrostatic test on a system within a home. A scope and a hydrostatic test are different tools, and for an older Richardson house you generally want both: the camera shows you condition and material, the hydrostatic test shows you whether the system holds water. For the broader sequence, our guide to the Texas home inspection during the option period covers what else belongs on the calendar.

How the Test Gets Authorized, and What the Repair Costs

Here is the piece that trips up even experienced buyers. You cannot order a hydrostatic test the way you order an inspection. The seller has to say yes in writing, on a specific form, separately from the contract.

On cost, be careful with any single number you read, including in this article. Dallas-area plumbing contractors publish ranges rather than rates, and those ranges are marketing material, not a survey. What they broadly agree on: a camera scope runs a few hundred dollars, spot repairs at an accessible break can land in the low thousands, trenchless lining of a full lateral commonly falls in the $5,000–$15,000 band, and full under-slab replacement with tunneling frequently runs $10,000–$25,000 and occasionally higher. Line length, depth, and whether the work runs under a slab or under a driveway drive most of the spread. Get two or three written bids on the same scope before any number enters a negotiation.

What happens next is a pricing and negotiation question more than a plumbing one, and Richardson's current conditions matter. Redfin reported a median sale price of $479,683 for August 2026, up 0.6% year over year, with a median of 33 days on market, a 97.7% sale-to-list ratio, and price drops on 41.6% of listings — up from 33.4% in June. Buyers in that market have room to ask, and they are asking.

For sellers, that argues for finding out first. If the line is sound, you have documentation that shuts the question down. If it is not, you get to choose your response — repair it, price for it, or offer a credit — instead of having the choice handed to you mid-contract. And once you know of a defect, it belongs on your Texas Seller's Disclosure Notice. Knowing early is what gives you options; it is not what creates the obligation.

For buyers, the practical move is to treat a pre-1990 Richardson house as a scope-it candidate by default, budget the few hundred dollars, and get the addendum signed up front. A clean report costs you a small fee. A skipped one can cost you a line item you inherit at closing. If the report comes back with problems, our guide to negotiating repairs after a Texas inspection walks through the options.