Although a lot of recent development has been taking place in San Antonio, TX, especially outside Loop 1604, much of the urban core is filled with old to very old homes that contain a host of defective materials installed with deficient and out of date techniques. One of the most common defective building materials is Galvanized-Steel water supply pipe.


What is Galvanized Water Supply Pipe?

Since the advent of plumbing, we have tried different materials to deliver water where it is needed. The Romans used stone, and then lead, some of which is still around today. Galvanized piping was used until the around the 1960’s, when copper piping entered widespread use.

Galvanized-steel pipe is a steel-based metal pipe that has been coated with zinc. Steel, being made of iron, will rust and corrode if exposed to oxygen (including water), so steel all by itself would not last very long as a water supply piping material. Instead, the steel pipe was electrically coated with zinc, a process known as “galvanization”, to serve as a water-resistant coating and extend its lifespan. This process works and is still used today on numerous building products, but we don’t use it for water supply piping because the life-expectancy of the material is not remotely as long as modern copper, PVC and PEX products.

deteriorated galvanized water supply pipe

Why is Galvanized Piping a Problem?

First, is the obvious problem that steel, even when coated with zinc, will eventually rust. The galvanized coating of the piping will eventually wear out, through erosion of decades of water running through the pipe. It takes a while, but it’s an inevitability. The pipe can rust from the inside or the outside, and both are problems. The exterior rusting creates weakpoints in the pipe that are more likely to break or leak. The rusting on the interior actually contaminates your drinking water with rust and iron. It is not uncommon for home inspectors in San Antonio to enter an older, vacant home, turn on a water faucet and begin to observe a brownish / reddish water discharging for a brief period of time. Over periods of time, this rust can cause health problems, especially if you don’t filter your water.

Second and less obvious, is the buildup of minerals inside the pipe. We have very hard water in San Antonio, TX due to the limestone found in the Hill Country and the Edwards Aquifer. This contributes large amounts of calcium carbonate into our water supply. While Calcium carbonate is not toxic, it will bind and adhere to many surfaces, including the inteiror of a steel pipe. This buildup, over a period of years, can actually reduce the diameter of the pipe, causing high water pressure at the fixtures and reduced water flow.

Something we check at every home is functional flow: we turn on the cold water at the kitchen faucet, go into the bathroom in the farthest part of the house where we turn on the faucet, and then flush the toilet: if we observe a reduction in flow at the faucet, that could mean the home does not have  functional flow. Lack of functional flow, often caused by restrictions in the galvanized water supply piping, can be really irriating for a small family, interrupting showers.

rusted galvanized water supply pipe

How do I know if I have Galvanized Water Supply Pipes?

Ask yourself if your home is built after 1960. If it is, you probably don’t have to worry. If it wasn’t, then look for some exposed sections of your water supply piping, such as around the water heater or inside the attic. If you have a pier and beam / crawlspace foundation, it is typically exposed in there as well. When you find some piping, beware that some galvanized piping was also used for gas-lines as well, which may confuse you. Look for copper-looking pipes; by copper-looking, it will look like a US penny. If you can’t find any copper pipes throughout your home and it was built before 1960, it is likely that you have galvanized water supply piping. As of February 1st, 2022, a home inspector in Texas is requried to report the materials observed serving as water supply piping, so you may consider hiring a home inspector if you are a home owner and you absolutely need to hire a home inspector if you are buying a home.


What is the Solution to Galvanized Water Pipes?

Unfortuantely, the real solution is replacement, also known as a “re-pipe”. A re-pipe entails removing the old galvanized steel water supply pipes and installing new copper or PEX water supply pipes. Re-piping the home’s water supply is a labor-intensive and costly ordeal, and you should shop around when collecting bids on the replacement, gauging what your options are. The extent of the replacement, the foundation type and other factors will all contribute to the final price. Make sure the plumber you hire is qualified and licensed, with insurance.

Alternatively, budget for replacement and know where your home’s water shutoff is so that if a line bursts, you know how to shutoff the water to limit the damage. Replacement of galvanized water supply pipe is a major investment that shouldn’t be taken lightly; we understand most folks can’t afford to just do this at the drop of a hat. So be prepared for the fact that your pipes may eventually leak and require replacement, and budget for it.


16400 Henderson Pass, STE 517
San Antonio, TX 78232

Hours of Operation

Mon - Sat 8:00AM - 8:00PM
Sun 10:00AM - 4:00PM

Professional Home Inspector Kyle D. Scott

TREC # 23813 - TDA # 819063

Ensure Home Inspection San Antonio TX provides thorough inspections, detailed reports, and personalized consultations at affordable prices in San Antonio & surrounding areas. Home Inspector San Antonio providing WDI/Termite Inspections, Thermal Imaging, Pool / Spa Inspections, Foundation Elevation Survey and more!

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