Question about Galvanized Steel

I have an offer on our potential first home. We love it and want everything to work out.

The inspector pointed out that the main water line coming from the street is galvanized steel and should be replaced. He turned on the kitchen sink, flushed a toilet, and pointed out that the faucet in the kitchen had a noticeable drop in pressure, and that indicates the water line is heavily corroded. With city water we should be able to turn on everything in the house and pressure should be strong.

The seller is saying his plumber checked the water line and it’s fine. Obviously I need to get my own plumber to check things out, so I’m going to look for one soon. The run from the street to the house is around 80 feet so it’s an expensive fix.

What is everyone’s opinion on this? Our inspector is telling us not to back down and get it fixed immediately.

Well galvanized steel is absolute garbage and yes most likely it is corroded on the inside of the pipe. But it's one of those things is it broken? No. Does it need to be fixed? No.

If you're still getting water to all the fixtures then there's no problem all because someone flushes a toilet and the kitchen sink dips a little bit in the flow does not mean this person is liable for replacing the whole main water line. If there was absolutely no flow to any faucet or fixture or the main water line was leaking then that's a different story.

If I was in your position I would tell this person to get it fixed immediately but if I was selling the home I tell you there's no problem and if you don't want to deal with it then don't buy the house

The drop in flow likely isn’t a water pressure issue, but a volume issue. It’s common for older homes to be plumbed entirely with 1/2” pipe. Fixtures can rob other fixtures with lower flow rates of their water. If the house was sized correctly I this wouldn’t happen. Replacing the galvanized line likely won’t change your situation.

Also, don’t pay too much attention to home inspectors. Unless he used to be a plumber he has no idea what’s going on with that pipe

Matt30 said:

The drop in flow likely isn’t a water pressure issue, but a volume issue. It’s common for older homes to be plumbed entirely with 1/2” pipe. Fixtures can rob other fixtures with lower flow rates of their water. If the house was sized correctly I this wouldn’t happen. Replacing the galvanized line likely won’t change your situation.

Also, don’t pay too much attention to home inspectors. Unless he used to be a plumber he has no idea what’s going on with that pipe

Click to expand...

All of the interior plumbing is new though.

It is probably the main feed to the house. And, you should definitely negotiate the replacement. Open the toilet tanks, and look for fine sediment, that might indicate that the line is near failure. Also, look in the tanks for rust stains.

If the feed to the house has developed chancre enough that it is retarding the flow to the house, it may be close to just rusting through. And, if you have copper plumbing inside, the bits of rust popping off can migrate in, and set up a half cell pin point corrosive reaction in the copper and cause it to fail.

The easiest way to check if it is the feed line, is to install a pressure gauge where the feed ties into the household plumbing. Record the static pressure, and then open successive taps in the house and see how much the pressure drops. When I first bought my house, the pressure would drop from a regulated 60-psi, to 40-psi with one tap on. If you flushed a toilet it would drop to 15-psi. I shut of the feed at the meter, and pulled the main valve to the house. The 3/4-inch steel line, had corroded to the point I couldn’t insert a pencil in the middle of it.

It is definitely worth investigating further, and a point to negotiate with the seller. You don’t want to buy the house, and end up with a very expensive repair in the first few years.

Yes it needs swapped out. No it shouldn’t hold up a real estate deal. “Garbage” is a vague term. If galvanized was junk it wouldn’t last 40 years before clogging. Check every pipe manufacture. Each only gives 20 year warranty. So most galvanized lasts a very long time but yes does corrode. City pressure varies. So just believing that you “should” have enough pressure doesn’t mean you will. I have installed a blue many of booster pumps on city pressure. So your new piping inside must be too small. And they probably used crimp pex. Which cuts flow dramatically. So yeah get a pro that doesn’t have corporate chomping at him to make numbers and get the truth. Inspectors look after whoever is paying his bill. So even then you got to be careful of him talking you out of a great home. 80 feet of water line would run about $1500-$2000. Maybe a little more depending on your area. Metro and bigger urban areas have so many utilities below dirt. You have to take more care and pull more permits. I would thread an airline cable thru galvanized and tie on new pipe at foundation go outside to meter and hook up a tractor and pull a new line in while removing the old. Even in digging 80’ should be a have day. So don’t get robbed. If you see your plumber on tv then your getting robbed. I always recommend to find the next small town over. Call that hardware store and utility district to see who they recommend. Talk with 3-4 plumbers before settling. Do not get the cheapest guy with a wrench with an hourly rate. He won’t be cheaper in the end. Good luck and god bless

Ok, folks: the head loss during flow, is a function of the hydraulic radius of the line, and the roughness coefficient of the pipe lining.

If the steel supply line line severely chancred on the inside, tow things have happened: the hydraulic radius has decreased, and the roughness coefficient has increased significantly. I’ve never calculated it for a service line but have done the Calcs on 8 to 24-inch ductile iron and the head loss is about ten time greater than ductile iron, and almost a hundred time greater than new plastic pipes. There is a whole industry, that specializes in putting new poly slip liners into aging water and sewer lines.

My personal experience with dealing with old steel feed lines both at home, and at work leads to the experience based knowledge that the head loss from an old steel service line can be huge.

As I said in my post above, if you want to determine whether there is significant pressure loss in the service line, all you need to do is install a pressure gauge as close to possible, to the entry, and record pressure from turning on taps. If you have a large drop from static to running, the kitchen sink, then adding a bathroom lavatory, and then a shower, you have large problem in the service feed. When it drops below thirty psi, fixtures don’t work as designed.

The whole house can have brand new pex, installed larger than code requires on all the lines, and if the feed line has significant head loss with flow, the fixtures won’t work right, and you won’t be happy with the flow if more than one fixture is in use.

I learned that the hard way. When I bought my house the previous owner had redone the entire house in pex, within a year of putting it on the market. And with just me in the house, running one fixture at a time, everything seemed fine. The first time I had family visit for the weekend it was obvious there was a problem, and the previous owner had tried to solve it by replumbing the house.

It took me a weekend to fix it, mostly because I’m a belt and suspenders kind of guy, and I installed a 2-inch poly sleeve, and then pulled a 1-inch pex with heat trace attached from the main to the house. And, because the old service entered at a mechanical room in the middle of the basement, I had to open a finished basement wall, and pull out thirty feet of staple up acoustic ceiling, to get the line to the mechanical room with out breaking the slab.

In conclusion: the plumbing in the house can be completely fine, and if the steel service line is severely rusted you will not have good flow at more than on fixture at a time.

The 1" galvanized supply line into our house is eighty-eight years old. Yes, there's some internal corrosion, but no, it's not garbage and no, it doesn't need to be replaced.

I had noted even though our supply line is 1", the city meter was 3/4". When they were converting to remotely read meters, I had them change it to a 1" meter and noticed improved flow to the sprinkler system.

As previously mentioned, until confirmed by gauge analysis, the pressure drop is as likely to be from recently installed PEX and flow restrictors as from a compromised original supply line. I installed a current best practice high dollar shower system and my wife said, "I think it doesn't give as much water as the old one." No, it doesn't because the PEX, the shower valves and heads have designed-in restrictions. Getting around those requires even higher dollar 3/4" high flow shower systems.

Slightly off-topic, but when the house across the street was having a supply line replaced, with copper BTW, I noted at the bottom of the hole in the center of the street, beside the current steel water main was a perfectly preserved wooden stave water main. I tried to bribe the crew to cut out a section for me, but they got to discussing how much jail time might accrue if discovered.

jack vines

I live in a older home. The 3/4" galvanized pipe is 86 years old and going strong. I wouldn't lose a house that you and your
wife love over a main water line. That line could last a long time yet. Did you look to see how the piping inside the house was done.

Might also look into relining, if that's a viable option. The pros on this site can give an aye or nay on that. My brother and I looked into it for a sewer line replacement.

TomFOhio said:

I live in a older home. The 3/4" galvanized pipe is 86 years old and going strong. I wouldn't lose a house that you and your
wife love over a main water line. That line could last a long time yet.

Click to expand...

The galvanized in our house is about 70 years old. The gate valve in the garage failed a couple of years ago and the plumbers replaced it with a ball valve. I still have a bit of the pipe they cut out to do that work. It is rusty on the inside, but there was plenty of metal left in the walls of the pipe. Flow is not a problem. What is a problem is that if anything bangs hard on a pipe a cloud of rust falls off and that can jam the first valve it runs into. About once every two years I have to take the hoses off the washer and clean out the accumulated rust in those filters. There are also flakes in the sink aerators which need to be cleaned from time to time, maybe twice a year. In short, there is a little bit of maintenance with the old pipes, but not nearly enough to warrant replacing them.

I expect when the galvanized does finally go it will probably fail at a joint and not rust through in the middle of a pipe.