I am experiencing hot water pressure issues and I'm assuming I have a blockage somewhere. It's most noticeable in the tub/shower, which is the furthest fixture from where the main water supply enters my house. However, there is a noticeable difference between hot and cold pressure at all faucets. Cold water pressure is great. The plumbing has been replaced fairly recently with copper pipes with the exception of a section before the water heater, but after the cold water supply split for the house which is still galvanized. My house is 75 years old. Whoever put in the copper did not use a dielectric union between the copper and the galvanized and now it is corroding. From what I can tell the galvanized piping only feeds an outdoor hose bib and the boiler in route to the water heater. The water heater looks fairly new. It has something about a code standard with a date of 1998 on it so I figure it can't be more than 9 years old. I live in Minneapolis which I believe has high water quality, so I would expect that the water heater is OK. I understand that other factors contribute to water heater quality, but I'm hoping that the problem is cheaper to fix than replacement of the water heater.

I plan to flush the water heater tonight to see if that helps. If it doesn't is it possible that the problem is with the old galvanized piping? It appears that the galvanized section is only 3 or 4 feet long.

Any other suggestions? I've ruled out the valve for the tub/shower because there isn't one. It's just a brass cross which looks to have been replaced when the copper was done.

Thanks,
Barry

Hey Barry,

Before you start to repair you must first isolate the problem. Is this a water heater problem?( clogged heater nipple). A problem with the faucets? (mineral build-up in the inlet ports of the cartridges) Or is it a volume problem? (Where something chokes down on the amount of water going through the pipes that pressure's affected) Let me know which one you think it is. Regards, Tom

Last night I flushed the water heater. After doing so I wanted to see if there was a blockage between the shower/tub (furthest fixture and the one with the most noticeable pressure issue) and the water heater.

1) I capped my shower head and turned off the cold supply to the water heater.
2) I left the cold supply to the shower on and turned on both the cold and hot water faucets in the shower, running cold water back through the hot water supply piping to the water heater.
3) I checked the water pressure at the hose I had hooked up to the water heater drain and it was fine.

Neither flushing the water heater or the hot water line did any good.

I think this tells me the problem is either with the inlet to the water heater or the stretch of galvanized piping before it.

Would you agree? If so, what would you do to fix it?

Thanks

I recently had the same problem. The culprit was a clogged (with corrosion) nipple pipe on the hot water outlet at the top of the water heater.

Turn Off the cold water inlet to the heater. Disconnect the hot water pipe connected to the nipple. Examine the inside of the nipple. I bet it's corroded & nearly completely blocked.

Cheers, Tom

Thanks everyone. I bypassed the old galvanized pipe and I've got great water pressure now. Woo hoo!