Can I replace the water pressure regulator in my home by myself or do I have to have a licensed plumber do it?
September 24, 2006 6:27 PM   Subscribe

Can I replace the water pressure regulator in my home by myself or do I have to have a licensed plumber do it?

I'm getting some noise in my water pipes, some hammering, and it seems to only happpen when I turn on a faucet somewhere in the house. The hammering is happening right by the main water shutoff in the house, which is right where the water pressure regulator is. The water pressure regulator looks like it is going bad at the joints...there is corrosion and gunk buildup going on, and it looks like that thing might even drip water from time to time.

I am very handy and would much rather replace the regulator myself, but is this a $500 job for plumbers only?
posted by thewiseacre to Home & Garden (7 answers total) 2 users marked this as a favorite
Depends on the code in your area but if you can turn the water off at the meter you can certainly replace the regulator. If it is showing corrosion definitely replace it, but banging pipes is generally a problem with pipes being correctly fastened down and having expansion stubs in the right places.
posted by ptm at 6:56 PM on September 24, 2006

Seconding ptm. Water hammer arrestors and expansion stubs do the same thing, which is to provide some compressible air space near the end of a pipe, to absorb the shock of moving water's intertia when a valve on the pipe is quickly closed. Replacing the pressure bladder near your water inlet may allow you to reset your water pressure to a lower level, which could reduce the hammer effect if your water pressure is unusually high, but it won't directly fix the hammer noise.
posted by paulsc at 7:04 PM on September 24, 2006

Response by poster: yeah, I figured that putting an arrestor in there would also be a solution, but two issues arose: 1) the arrestor I bought, which was the biggest size copper they had, is only 3/8" and the pipe that is hammering is a 3/4" or maybe bigger because it is right by where the main shutoff valve is inside my house and b) when I was looking at the pipe up close, that's when I noticed that the connecting threads on the regulator were showing wear and mineral deposits.

I'm kind of scared to put a reducing joint on the pipe at that location in order to add on an arrestor, first because of the pressure there and second because I'm afraid I won't do a good soldering's like 15 feet off the ground, a tricky spot up by the floor joists, etc. I don't wanna pay $500 but in the end, this might really be a job for an actual plumber.

The water pressure doesn't seem unusually high in our house, but my bet it's on the high end of the tolerance allowed (80 or so.)

I looked at Lowes but didn't see regulators there. Do I have to go to a more specialized store to find regulators, or are they hidden in a less obvious place (by water heaters?) in the store?
posted by thewiseacre at 7:54 PM on September 24, 2006

Best answer: An arrestor is only going to work well on a branch pipe, far away from the main water inlet, near the end of the branch pipe; so, 3/8 or 1/2 inch is the normal copper tubing size. You'd probably do better than Lowes or Home Depopt, by getting a replacement pressure regulator from a plumbing supply house in your area; there should be listings in the Yellow Pages.

A pressure regulator works on an entirely different principle. A cross-section drawing of a pressure regulator is shown on this page. You may be hearing the "knocking" sound from the general area of the inlet regulator, but most likely what you're hearing is not actually a water hammer knock, as much as it is an internal spring or pressure diaphram broken, and causing noise. If there is a union joint near the regulator, replacing one is about a 30 minute job, since the union joint makes removing the old one a simple process. Just shut off the water, break loose the union joint, and turn out the pipe back to the regulator, and then the regulator. Install the new one in reverse assembly order.
posted by paulsc at 8:30 PM on September 24, 2006 [1 favorite]

Best answer: When in doubt, call a pro. If it's really a $500 job, you can probably get a free estimate -- and thus find out exactly what the deal is, instead of worrying and speculating about it. (Armed with the knowledge, you can then decide if you want to do it yourself.) If it's not a $500 job -- or if it's not the problem you think it is -- it's worth 75 bucks an hour plus materials for the peace of mind.
posted by turducken at 10:40 PM on September 24, 2006

Response by poster: thanks to all for your help!
posted by thewiseacre at 6:37 AM on September 25, 2006

Most water hammer and associated "knocking' is caused by excess water pressure at the incoming main or fast shutting valves.When the pressure is high and the pipes reduce in size the velocity increases substaintially.This will cause water hammer just as easily as fast closing valves will.Water hammer is due to water being 'essentially" non compressible (at least in normal pressures encountered in life) When the water path is suddenly stopped the inertia of the water will continue thru the system increasing in pressure until it peaks.Water hammer can have peaks in the 300 psi range!!!

Hammer arrestors work in local installations but if the problem is not just at that device (like a washing machine solenoid) then installing multiple arrestors is an expensive solution to the symptom not the cause.Improper piping installations cause it too E.G. a dishwasher supply should be 1/2 diam up to 12" from the device.Many install a few ft of 3/8 tubing instead for ease but this may cause water hammer due to the fast solenoid and the increased velocity.

Maximum incoming water pressure by code here is 78 psi.If your incoming pressure is higher than that then I would install a pressure reducing regulator.!!!!!! If you do it your self make sure you order a hot water bypass option regulator!!!!! Hot water tanks have a certain amount of natural expansion into the cold water line and if you do not install the proper regulator your pressure and temperature release valve on the HWT will intermittenly discharge (maybe even full discharge) and cause potential damage.

Most areas allow homeowners to do self plumbing repairs etc but you may not have a leg to stand on with your insurance company if your work causes damage.If you feel confident in your skills,by all means try the install.You should have valves and a drain on the meter so isolating a draining to solder should be fairly easy.As usual PaulC gave great advice re a union etc.

One tool I really recommend home plumbers to get is the jet sweat or similar


This allows a valve to be soldered on even if the water will not completely shut off.I have been on tooooo many calls where the homowner got into trouble due to water not allowing them to solder.
posted by plumberonkarst at 7:24 AM on September 27, 2006

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