If your water bill suddenly jumped 30% or more with no change in how you use water, you almost certainly have a leak — and in our experience, roughly 8 out of 10 of those calls turn out to be a running toilet, a leaking irrigation valve, or a hidden supply line leak under a slab or crawl space. The fastest way to confirm it: shut off every fixture in the house, then watch the low-flow indicator on your water meter for 15 minutes. If it moves at all, water is escaping somewhere between the meter and your fixtures, and it's costing you money every hour until it's found.
Start With the Meter Test — It Takes 15 Minutes
Before you start opening walls, find out whether the leak is real and whether it's on your side of the meter. Most homes in Tigard, Tualatin and Sherwood have the meter in a plastic or concrete box near the sidewalk or driveway apron. Pop the lid (a long flathead screwdriver works), wipe the glass, and look for the small triangle, star, or red dial — that's the low-flow indicator, and it spins with as little as a quarter-gallon per hour moving through the pipe.
Turn off all faucets, the ice maker, the irrigation controller, and don't flush anything. Mark the indicator position, wait 15 minutes, and look again. Movement means a leak. Next, close the main shutoff at the house (usually in the garage, crawl space hatch, or on the front hose bib wall) and repeat. If the meter stops, the leak is inside or under the house. If it keeps creeping, the leak is in the service line between the meter and the house — a repair we do several times a month in older Beaverton neighborhoods with galvanized or early polybutylene service lines.
1. Toilet Flappers — The #1 Culprit, By Far
We've serviced hundreds of "mystery bill" calls in Washington County and the toilet wins almost every time. A worn flapper lets water seep from the tank into the bowl silently, and the fill valve tops it off over and over. That's 200 to 1,000 gallons a day from a $12 part. Test it: put 10 drops of food coloring in the tank, don't flush for 20 minutes, then check the bowl. Any color in the bowl means the flapper is leaking. Chlorine tablets dropped in the tank chew through rubber flappers fast — if you use them, plan on replacing the flapper every year or two.
2. Irrigation Systems and Outdoor Valves
Sprinkler leaks hide well because the water disappears into the lawn. In our Hillsboro and Lake Oswego service calls, the usual failure points are a cracked manifold fitting, a valve diaphragm that won't fully seat, or a sheared riser from a lawn mower. Watch for one zone that's greener and soggier than the rest, or a puddle near the backflow device. Because irrigation branches off before most indoor fixtures, a leaking zone valve can dump water 24/7 even with the controller set to "off."
3. Slab Leaks and Crawl Space Supply Lines
Plenty of homes here sit on slab or over a vented crawl space, and a pinhole in a pressurized copper or PEX supply line runs constantly. Signs we look for: a warm patch on the floor (hot side leak), a water heater or recirculation pump cycling more than it should, a musty smell, or the sound of running water with everything off. In crawl spaces we often find corroded galvanized nipples and old compression fittings weeping onto the vapor barrier. If you spot standing water or rusty streaks under the house, get a professional on it — targeted pipe repair is far cheaper than the framing and insulation damage that follows a few months of unnoticed leaking.
4. Water Heater Temperature & Pressure Relief Valve
The T&P valve on the side of the tank has a discharge tube running to a floor drain or outside. If system pressure is too high or the valve seat is fouled, it drips continuously and you'd never see it. Put a dry cup under the discharge tube end and check it the next day. While you're there, thread a $10 gauge onto a hose bib — anything above 80 psi is out of code and hard on every fixture in the house. High static pressure is one of the most common underlying causes we find behind repeat leaks in newer Sherwood and Tualatin subdivisions.
5. Hose Bibs, Washing Machine Valves, and Fill Lines
Freeze-damaged hose bibs are a January-through-March special in the Portland metro. A frost-split bib often leaks only when the shutoff is open — and if you left a hose attached through a cold snap, the split may be inside the wall where you can't see it. Check the washing machine hoses and the shutoff valves behind the drywall panel too; braided stainless hoses have a real service life of about 5 to 7 years.
6. The Service Line Between Meter and House
This is the expensive one. If the meter keeps running with the main valve closed, the buried service line is leaking. In our experience these show up as a soft or unusually green strip in the yard, a drop in pressure at fixtures, or gravel and driveway settling. Older galvanized steel lines and 1970s–80s polybutylene are the usual suspects. Depending on the route and depth, we either spot-repair the section or replace the run.
If you've run the meter test and the needle is still moving, don't wait for the next bill to confirm it — a 1/16-inch pinhole wastes about 100 gallons a day and quietly damages framing the whole time. Hydro Plumbing (CCB #254405) does leak location and repair throughout Washington & Yamhill Counties, including Tigard, Beaverton, Hillsboro, Lake Oswego, Tualatin and Sherwood. Call us at (971) 241-2628 and we'll find it, document it for your utility's leak credit, and fix it right the first time.