Why Is My Water Bill So High? 5 Common Causes in Everett Homes

The average Snohomish County household uses around 4,500–6,500 gallons of water per month. When the bill suddenly looks like double that — or even just 30–40% above last month for the same time of year — something’s wrong. We’ve gotten enough “why is my water bill so high” calls to know the five usual suspects, in order of how often each turns out to be the actual cause.

The Five Most Common Causes (Ranked)

1. Running toilet. The #1 cause by a wide margin. A toilet with a failing flapper can waste 200–4,000 gallons per day — silently. The dye test (10 drops of food coloring in the tank, wait 20 minutes, check if it appears in the bowl) catches this in 5 minutes. Replacement flapper costs $5.
2. Hidden underground supply line leak. The line between your meter and the house develops a leak that doesn’t show above ground. Bill spikes, ground stays dry for a long time before any visible signs appear. Common in older Everett homes (1950s–80s) with original galvanized service lines. Our piece on underground water leak signs covers detection.
3. Irrigation system leak or stuck valve. If you have an automatic irrigation system, a stuck zone valve can run for hours without anyone noticing. Even a partially failing valve can dramatically increase irrigation runtime. Check zone controllers and look for unusually wet patches in the yard.
4. Leaking water heater. Slow seepage from a failing tank water heater. Often the unit dumps water continuously into a drain pan that drains to an exterior point, so you never see the puddle. The meter is reading every gallon.
5. Increased actual use. Sometimes the simple explanation is the right one. New family member, longer showers, more loads of laundry, a kid who left the hose on overnight. Worth ruling out before assuming a leak.

The 30-Minute Diagnostic

Three steps to find the cause without calling anyone.

Step one — the meter test. Turn off every water-using fixture and appliance. Locate your water meter (typically at the curb in Everett). Read the current value. Wait 30 minutes without using any water. Read again. If the meter moved at all, you have a leak somewhere in the supply system. The faster it moved, the bigger the leak. If it didn’t move, you’re looking at either a fixture issue (running toilet, slow drip somewhere) or an actual use change.

Step two — toilet check. Dye test every toilet. About 30% of running toilets are visually undetectable (no sound, no visible water movement) but waste hundreds of gallons per day. Dye test catches all of them. Cost: nothing. Time: 20 minutes.

Step three — irrigation check. If you have an irrigation system, manually run each zone in sequence and watch how it behaves. A zone that won’t shut off cleanly, takes longer than scheduled, or has visible pressure issues is suspect. Our walkthrough on leak detection methods covers the broader diagnostic approach.

When to Stop Diagnosing and Call

If the meter test showed movement but you couldn’t visually find the leak, you’re at the call stage. Hidden leaks in walls, under slabs, or in buried supply lines need professional detection tools — thermal imaging, acoustic listening, pressure isolation testing. None of these is DIY-friendly.

For Everett homes specifically, the buried supply line is a common culprit, particularly in homes 30+ years old. Catch it before the bill triples. Most insurance covers sudden line failures but not slow leaks that show up on bill comparisons over months — which is why catching them early matters financially as well as practically.

Our expert leak finding team can pinpoint hidden leaks same-day with non-invasive tools. Or reach our Everett plumbing crew directly to schedule the diagnostic.