Rapid corrosion in galvanized water pipe

[California]

What should I do for rapid corrosion in galvanized water pipe?

In the past 3 years I've found leaks and replaced pipe at two water heater joints and a joint where the supply from the well meets the house shutoff. In these three cases the materials are less than 10 years old and it is a galvanized to brass (or copper flex) connection. I've also replaced a rusted-through warm water pipe under the bathroom and a leaking copper tube feeding its washbasin. Plus put a clamp on a leaky line in the garden.

Six instances fixed so far, and there are several more places showing rust at threaded pipe joints.

The water has tested acidic but well within drinking water limits. There is no softener etc.


Any advice on how to slow this down?

 

[Cliff_Johns]

You should take a look here galvanic reaction page

In general, you have a connection of disimilar metals which is almost always a bad idea and causes one of the metals to self destruct. You need to isolate the copper or brass from the galvanized metal.

Cliff

 

[PineRidge]

Electrolysis, that's what you're up against. Dissimilar metals reacting against each other. There are ways to slow it down but it can't be eliminated. Ask the boat guys about anodes. Ask the water heater guys about sacrificial rods.

 

[Phils]

And one other (slim) possibility. I had some rapid corrosion and traced it to a bad well pump. There was an internal partial short in the pump or wiring, enough to cause a slight 'tingle' if you were grounded and touched the water coming directly from the well. That small electrical charge caused electrolysis to happen much faster... ate through a couple of water heaters (house and RV) before I figured it out... and then only because I was letting some water out near the well and felt the "tingle".

Phil

 

[JDgreen227]

There are fittings called dielectric unions that are used to connect plumbing pipes of different metals, and the most common are the ones used for galvanized pipe connecting to copper lines. Our original house had sections of galvanized pipe over 50 years old that were still solid although the water running through them was slightly acidic. Some people seem to think that wrapping a lot of teflon tape around a galvanized male pipe end before threading it into a female copper fitting delays the corrosive action.

I'm not one of them. /forums/images/graemlins/wink.gif

 

[Av8r3400]

A ph test may also be in order. This tests the acidity or alkalinity of the water. My water at home is quite acidic and would have eroded the copper plumbing quickly if I had not installed a neutralizer.

 

[dbelisle]

Have your water tested a take a look at a water softener. I used to replace traps. water heaters, and other parts of my plumbing system on a regular basis for 15 years.

I finally broke down a installed a water softener. The better half is much happier. The fixtures are easier to keep clean, the cloths wash better, and I am not replacing plumbing parts all the time.

Even with the water softener I spend the extra money and use brass, copper , or Pex . I don't use galvinized on well water.

I may seem expensive but in the long run it is cheeper.

Dave in NH

 

[willywildes]

I believe that installing Dielectric Unions is your answer. if you run copper and it touches any other metal the copper will start to turn into a sprinkler system[pin hole leeks] under your house. The galvanized will do the same. the union is needed where dissimilar metals meet.
Good luck!
WW.

 

[reb]

I agree that dielectric unions are the answer. As I understand, the building code requires them in most locales.

 

[Av8r3400]

Softener did litle or nothing for the acidity of my water. I had to add a neutralizer too. This brings the PH value to neutral, then the corosion stopped.