Skip to Main Content
View / Pay Bill
Quicklinks
EXPLORE

How to Find Leaks

The best way to determine whether you have a leak in your plumbing is to check your water meter. If you do not know where your meter is located you can call customer service at (425) 787-0220 for help.

Checking your meter for a leak

Below are written instructions for checking for leaks. You can also watch these videos provided by Saving Water Partnership.

Meter Box Lid

STEP 1: Turn off all water-using appliances and fixtures inside and outside of your home or business. Use no water during the test period.

STEP 2: Locate your water meter at the front of your property, usually in a concrete or plastic box near the edge of the road. Open the lid, the meter box may be full of dirt or water.

STEP 3: Check to see if the leak indicator is moving. Depending on the brand of your meter, the leak indicator could be a small triangular shaped dial or a small wheel that rotates when water is flowing through the meter. If the dial is moving, chances are, you have a leak.

Meter Diagram

OR, if you’re unsure about the leak indicator, record the current meter reading. Then wait about 30 minutes without using any water inside or outside. Check the meter again and compare readings. If the reading has changed, it’s likely there is a leak in your system.

After you have determined that you have a leak, the next step is to determine if the leak is inside or outside of your house.

STEP 4: Locate your home’s main shut off valve and shut off the water at the valve. Typically, you will find the shut off valve in the basement or garage directly behind an outdoor faucet, or outside below an outdoor faucet.

STEP 5: Check the leak indicator again for movement or use the meter reading method, making sure not to use any water during this period. If the leak indicator stops moving or there is no change in the meter readings, then you have a leak inside of the house. If the leak indicator continues to move or there is a change in the meter readings, then the leak is outside between the meter and the house.

STEP 6: If you are unable to locate the leak, you may need to call a plumber.

Water is a limited resource and it is the responsibility of all water customers to maintain their pipes, fixtures, and irrigation systems to minimize unintended loss of water. Nevertheless, on rare occasions, unexpected water use can occur through no fault of the customer. In the case of a water leak customers may be eligible for an adjustment on their bill. Please view the Policy and Application for Leak Adjustment in the menu to the right.

The usual suspects – indoor leaks

Faucets

Leaking faucets are generally a result of a worn rubber washer. The washer on a sink is usually located under the handle. These are relatively easy to replace, if you have the right tools. It does require shutting off the water under the sink or at the main shutoff valve and removing the handle. (Note: faucet handles are not shutoff valves.) Check your local home center or hardware store on how to repair faucet leaks.

Toilets

Toilet leaks can waste hundreds of gallons and often times are silent. Even a small leak can add up to a lot of wasted water and money over time. Fortunately, most toilet leaks are easy and inexpensive to repair.

To help determine if you have a leaking toilet, simply remove the tank lid and place a few drops of food coloring in back of the toilet tank. (If you don’t have food coloring, you can purchase dye tabs from any hardware or home center). Wait about 30 minutes, without flushing, and then look in the toilet bowl to see of any color has come through. If the water is clear, water is not leaking. If you see food coloring in the bowl you have a leak.

In most cases, you will simply just need to replace the toilet flapper and/or filling mechanism. These are typically available at hardware or home center stores for under $20.

Flapper Valve Leaks

The most common reason for a leaking toilet is one that has an improperly working or sealing flapper. The flapper is the rubber valve in the bottom of the tank that lifts up when the toilet is flushed. If the flapper is worn or cracked, it allows water to continuously flow from the tank into the toilet bowl without flushing.

Flush Handle Problems

If the handle needs to be jiggled to keep the toilet from running, the flush level bar and chain (or the handle itself) may be sticking. Adjust the nut that secures it in the toilet tank. If that does not work, the handle may have to be replaced.

Overflow Tube Leaks

Ideally the water level should be set so that is about even with the fill line on the back of the toilet tank (approximately ½” below the overflow tube). If the water is too high in the toilet tank and is spilling into the overflow tube, the water level can be adjusted by turning the adjustment screw or by very gently bending the float arm down so that the water shuts off at a level below the overflow tube.

Note: If none of these steps solve the problem, you may need to contact a plumber to repair or replace the toilet.

Finding Other Water Leaks

The water you drink and bathe with is delivered under pressure, so a leak can be very obvious. Wastewater, on the other hand, is usually moved by gravity and is not under pressure. This makes wastewater leaks much harder to detect. If you suspect a wastewater leak, please call our Maintenance & Operations department for help.

Be aware that the exact location of a leak may not always be immediately obvious. Some leaks may start at one location, then flow along a ledge or other channel for a distance before they drain down and create some visible damage.

Look for wet, warped or discoloration stains on your ceilings, floors, walls and woodwork (such as the bottom of your kitchen or bathroom sink cabinet). As you attempt repair, be sure to check twice for the actual location of the leak, not just the resulting damage from the leak.

Condensation can also be a form of water leak. While condensation is normal, excessive condensation can cause damage to your walls, ceilings, floors and woodworking. If there is too much condensation, insulating your pipes may stop or reduce the condensation.

Underground Leak Detection

STEP 1: Look (and feel) for portions of your property that are always wet.

STEP 2: Look at your driveway, curb or street for evidence of water flow. The evidence may not be a steady stream of water; it may only be a puddle that never dries up, or a darker spot (as in what happens when water is spilt on dry concrete).