Weird Water Pressure Thing

[mensa]

Hoping someone can shed some light or at least point me in a direction to help me solve this.

We are on municipal water, and have a flow meter installed. Our pipes are 5/8".

For the last month, I've noticed that our water pressure has dropped quite low - i.e. there's barely enough water to rinse the soap from your hands after you flush the loo.

We had a widespread four hour power outage here yesterday, as a result of a freezing rain storm (in April!!! Bloody Canadian weather!) While the power was out, our water pressure returned to normal. As soon as the power came back on, the pressure dropped.

WTH would cause that? I just can't work it out. We do have a filter on the system, and it's possible that the filter needs to be changed, but I can't see that this is the core issue, since electricity has nothing to do with that.

I plan on contacting our utility company on Monday, but I'm hoping not to sound like some kind of whack job. Anyone got an idea what could be limiting our pressure when the power's on?

[MooreBonds]

Solely based on your description of 'regular' pressure when the power was out, and then low pressure when the power came back on, would make me guess if there's a large industrial user that is constantly drawing water that drops the pressure in the main.

At first I would have suggested some debris might be caught somewhere between the main and your interior house piping....but that wouldn't really raise the pressure when the power is out, and then drop the pressure when the power goes back on.

It wouldn't hurt to contact the utility and tell them your experiences.

[Nords]

We are on municipal water, and have a flow meter installed. Our pipes are 5/8".
For the last month, I've noticed that our water pressure has dropped quite low - i.e. there's barely enough water to rinse the soap from your hands after you flush the loo.
I plan on contacting our utility company on Monday, but I'm hoping not to sound like some kind of whack job. Anyone got an idea what could be limiting our pressure when the power's on?

Your utility company may tell you to go get a plumber.  95% of the time the problem is not their water piping (which ends at the isolation valve from the street) but with your house piping (which starts at the outlet of the water utility's street valve). 

It sounds as if your water pressure regulator may be dying.  (Especially if it's older than 10 years.)  Its inner spring or diaphragm may be getting stuck or brittle, and when the water pressure drops it's not opening up the flow from the street valve to allow pressure to recover. 

Many regulators have a hex nut on top that you can adjust with a wrench.  You could note its original position (use a marker or a grease pencil or a scribe) and then exercise it a half-turn in each direction to free the spring from any corrosion or peanut butter that may be preventing its motion.  If you look down on the nut from above, and turn it a half-turn counter-clockwise (lefty loosey) then hypothetically that'll cause it to regulate the house water pressure at a slightly higher number.  (There's a slight risk that something will jam or fracture, too, and then it won't regulate at all.)  If you have a pressure gauge that you can screw onto an exterior hose bib then that makes the whole tweaking evolution a lot easier.  You can stand at the pressure gauge and have someone flush a toilet in the house (or turn on a faucet to max) and then see if the water pressure recovers.  You can tweak the regulator's adjustment nut and see how the pressure gauge reading changes.

Also hypothetically, you can buy a water pressure regulator at any big-box home improvement store and install it with a couple of 12" Ford wrenches.  I've done several of them and the plumbing challenge is taking rusty piping apart without breaking anything.  The real problem with the repair is that it's a high-pressure job of another type:  people are standing over your shoulder asking "Is it done yet?" or offering helpful suggestions, or the street isolation valve leaks when you try to shut off all the water, or you have trouble accessing the piping, or trouble aligning it to get a leakproof connection.  So if you're not comfortable with replacing a toilet or a kitchen faucet, then I would definitely seek professional help for this job.

[mensa]

Thanks for the replies.

Nords - your "lefty loosey" made me grin. No doubt I'm going to sound like an idiot here, but I don't think we have a pressure regulator on our system. The flow meter (installed by the utility a year & a half ago) is for usage recording/billing purposes. I'm lead to believe that all it does is record usage. If it does have some kind of sneaky regulator, why would it stop functioning when the power is off?

We did cut our main power to test if the issue (as regards the electricity/pressure weirdness) was something in our house. There was no difference to the water pressure when only our power was off.

MooreBonds - your hypothesis seems plausible. If that is the issue, I'm not giving myself great odds at getting the issue resolved, which blows.

Will call utility company and see what I can find out.

[galaxie]

If someone nearby is using so much water that it drives your water pressure down, your neighbors might be experiencing this too.  Asking them would give you another clue.

[Nords]

Nords - your "lefty loosey" made me grin.

"Lefty loosey" is a nuclear engineering technical term used for the challenge of training Navy ensigns.  We've been developing that highly sophisticated vocabulary for over 50 years now.  For example an advanced mechanical fastener with a left-handed thread would be "righty roosey".  But most regulators use a right-handed thread.

No doubt I'm going to sound like an idiot here, but I don't think we have a pressure regulator on our system. The flow meter (installed by the utility a year & a half ago) is for usage recording/billing purposes. I'm lead to believe that all it does is record usage. If it does have some kind of sneaky regulator, why would it stop functioning when the power is off?

We did cut our main power to test if the issue (as regards the electricity/pressure weirdness) was something in our house. There was no difference to the water pressure when only our power was off.

Will call utility company and see what I can find out.

I'm using the word "regulator" to indicate a device that maintains something like water pressure.  Regulators have been around long before electricity, and mechanical regulators have been around for centuries.  It has nothing to do with your flow meter, and I didn't even use those words in my first response.  The utility meter is a completely separate device, and they don't want to be anywhere near the customer's ragged regulator.  Tomorrow they're probably going to suggest that their flowmeter is fine but that your regulator sucks, although they may use more tactful terms.

You're looking for something like one of these:
http://www.poway-plumbers.com/wp-content/uploads/2010/01/ar1237333838700922.jpg

They're made out of brass, but sometimes they get painted or otherwise camouflaged.  It might be inside your garage or your utility room, it might be in your basement, or it might be outside in a box below grade level.  You could start at the utility's water meter and see if you can trace the pipe into your house.  The regulator should show up before you get to the water heater.  If you live in a 20th-century planned neighborhood (houses built by a developer at about the same time, not one at a time over years or decades) then the houses were almost certainly built to a plumbing code which included water pressure regulators.

The regulator is completely mechanical and does not need electricity.  The reason it seemed to be working so well when the power was off is because (1) some totally unrelated coincidence or (2) demand on the water system was greatly reduced (the power was out so nobody was taking showers in their dark bathrooms or doing laundry or able to run their lawn irrigation systems or cooking dinner or running water pumps in their factories) and street water pressure was high enough for even your regulator to have enough to work with.  But as soon as the power came back on and people started using water again (as a byproduct of having electricity available to see what they were doing and to help do it) then the pressure at the street meter dropped and your regulator wasn't able to open itself up enough to raise the pressure in your house's water piping.

I've experienced all of the symptoms you've described, and I've fixed them by replacing the water pressure regulator.

[mensa]

Nords - thanks for the detailed suggestion (and the picture - handy!). I traced the piping from where it enters the house to the water heater and there was nothing attached to the pipe. I'm not in a neighborhood as you describe, so maybe that's why. Or, as you suggested, perhaps it's boxed in underground.

Lefty loosey reminded me of my father teaching me to use a screwdriver. His terms were "righty-tighty" and "lefty-loosey". I still hear this in my head whenever I'm un/screwing anything.

[mensa]

Just a follow up:

As it turns out, you were correct Nords: It was a completely unrelated coincidence that the pressure returned when the power was off. The issue was with the whole-house filter system. Before calling the utility, I by-passed the filtration, and the pressure burst forth like a fat kid on a Smartie.

[Nords]

As it turns out, you were correct Nords: It was a completely unrelated coincidence that the pressure returned when the power was off. The issue was with the whole-house filter system. Before calling the utility, I by-passed the filtration, and the pressure burst forth like a fat kid on a Smartie.

Thanks for posting the update.

If the bypass doesn't leak then changing out the filter will save you a lot of money on plumber's bills.  Heck, even if it leaks you can probably still make the repair without things getting too messy.