The Quick Answer
A sudden spike in your Michigan water bill — without any obvious change in household habits — is one of the most reliable signs of a hidden plumbing leak. Common culprits include running toilets, dripping faucets, leaking supply lines, slab leaks, and underground service line damage. This guide walks through how to diagnose the cause, what to check yourself, and when to call Kenowa Plumbing for professional leak detection.
You open your Grand Rapids water bill and something’s wrong. Your usage is double — or triple — what it was last month. Nothing changed in your household. You haven’t filled a pool, run sprinklers all day, or had a party. So where’s the water going?
The most likely answer: somewhere in your home’s plumbing, water is running continuously without you knowing it. Depending on the leak’s severity, you could be losing hundreds or even thousands of gallons per day. This guide is your starting point.
Step 1: Confirm You Have an Active Leak — The Meter Test
Before calling a plumber, do this quick test to confirm water is actively flowing somewhere in your home:
| The 15-Minute Meter Test Turn off all water in the house — no faucets, no toilets, no ice maker, no appliances. 2. Locate your water meter (usually near the street, in a covered box). 3. Note the reading — most Grand Rapids meters have a flow indicator or a small triangle/dial that spins when water is moving. 4. Wait 15 minutes without using any water. 5. Check again. If the indicator moved or the reading changed, you have an active leak somewhere. |
If the meter didn’t move during the test, your water bill spike may have a different cause — check for billing errors, seasonal rate changes, or one-time high-use events you may have forgotten. If the meter did move, keep reading.
Grand Rapids Water Meter Reading Tips
Grand Rapids uses Sensus automatic meter reading (AMR) meters. Your meter box is usually in the curb strip near the street. The sweep hand or digital readout changes in cubic feet or gallons. Many Grand Rapids customers can also access hourly usage data through the city’s online portal — this can help you pinpoint what time of day the usage spikes.
The Most Common Causes of a High Water Bill in Michigan
Here’s what we find most often when investigating unexplained water bill spikes in West Michigan homes:
Running Toilet — The #1 Culprit
A running toilet is the single most common cause of unexplained high water bills. A toilet with a failed flapper or fill valve can waste 200–500+ gallons per day — silently, continuously, day and night. The insidious part: you often can’t hear it from across the room, and it doesn’t show any external signs. Add food coloring to the tank (not the bowl) — if color appears in the bowl without flushing, you have a running toilet.
Dripping Faucets and Fixture Leaks
A faucet dripping once per second wastes approximately 3,000 gallons per year — roughly equivalent to 180 showers. A faster drip or a faucet left slightly open compounds quickly. Check every faucet, showerhead, and outdoor hose bib. Don’t forget the supply line connections under sinks.
Underground or Outdoor Leaks
Leaks on the service line between the water meter and your home — or in underground irrigation systems — can be large and completely invisible inside the house. Signs include unexplained wet patches in the yard, sinkholes or soft spots over where the line runs, or unusually lush green grass in one section of the lawn. These are more expensive repairs but important to address quickly.
Slab Leaks
Homes with plumbing running through a concrete slab (common in some Grand Rapids-area neighborhoods) can develop slab leaks — pipe failures where water escapes underneath the foundation. Signs include warm spots on the floor, the sound of running water with everything off, water damage along baseboards, or sudden hot water shortages. Slab leaks require professional acoustic or infrared detection and are among the more serious hidden leaks.
Water Heater Pressure Relief Valve
The T&P (temperature and pressure) relief valve on your water heater is designed to open if the tank overheats. If this valve fails in a partially open position, it can drain continuously into the floor drain — wasting thousands of gallons while you’re unaware. Check if the discharge pipe from your water heater’s T&P valve is dripping or warm.
Supply Line Leaks Behind Walls
Small pinhole leaks in copper, CPVC, or PEX supply lines inside walls can run continuously without making it to a floor drain — instead saturating wall insulation and creating moisture damage that remains invisible until it’s significant. These typically show up as damp drywall, musty smells, or discoloration on walls and ceilings.
Leak Diagnostic Guide: Match the Symptom to the Source
| Symptom | Likely Source | Recommended Action |
|---|---|---|
| Meter moves with all water off | Active leak somewhere in the system | Do isolation test (see below) to narrow location |
| Running water sound with nothing on | Running toilet, running fill valve, or slab leak | Check toilets first; listen near floors |
| Warm or hot spot on floor | Slab leak on hot water line | Requires professional acoustic detection |
| Damp wall or ceiling stain | Supply line or drain leak inside wall or ceiling | Professional detection recommended; don’t delay |
| Wet yard / lush patch in lawn | Underground service line or irrigation leak | Check meter box for moisture; call for service line inspection |
| T&P discharge pipe warm or dripping | Water heater relief valve failure | Do not cap the discharge pipe — call Kenowa Plumbing |
| High bill but meter test shows nothing | Billing error or one-time event | Contact Grand Rapids Water Utilities to review usage data |
| High bill only in summer months | Irrigation system leak or outdoor hose use | Check all irrigation zones and outdoor hose connections |
What You Can Check Yourself vs When to Call a Pro
Check These Yourself First
Running toilet test (food coloring in tank). Dripping faucets and showerheads. Visible water under sinks or around base of toilets. Outdoor hose bibs and hose connections. T&P valve discharge pipe on water heater. Irrigation system heads and zone valves (if accessible).
Call Kenowa Plumbing for Professional Detection
Any leak you can’t see or locate after checking the obvious sources. Suspected slab leaks (warm floors, water sounds with nothing on). Wall or ceiling moisture without a visible source. Underground service line or irrigation main leaks. Any situation where shutting off the water temporarily revealed the leak is inside the house but you can’t locate the section.
Professional leak detection uses specialized tools that locate water without destructive investigation:
- Electronic acoustic leak detectors: Amplify the sound of water escaping pressurized pipes to pinpoint leaks through floors, walls, and concrete.
- Thermal imaging (infrared): Identifies temperature differentials created by water movement behind walls or under floors — no demolition required.
- Pipe pressure isolation testing: Isolates sections of the supply system to confirm which branch the leak is in before opening walls.
- Video inspection: For drain lines and service lines, a camera confirms the location and nature of the problem.
| The cost of professional leak detection is almost always far less than the cost of the water waste, water damage, and mold remediation that follows when a hidden leak is ignored. The earlier you find it, the less expensive the repair. |
The Isolation Test: Narrowing Down Where the Leak Is
If your meter test confirmed an active leak, this isolation test helps determine whether the leak is inside or outside the house — which determines the urgency and scope of repair:
- Locate Your Main Interior Shutoff
- Find the main shutoff inside your home — typically near the water meter connection, in the utility room, or in the crawl space. This valve controls all water inside the house but leaves the service line between the street meter and the house active.
- Turn Off the Interior Shutoff
- With all water off inside the house, close the main interior shutoff.
- Go Back to the Street Meter
- Check whether the meter indicator is still moving. If it stops: the leak is inside your home. If it continues: the leak is on the service line between the meter and the house, or in an outdoor irrigation system.
If the leak is inside the house: The leak is on your interior supply lines. Check toilets, faucets, supply lines, and water heater first. If you can’t find it visually, call Kenowa Plumbing for professional detection.
If the leak is outside the house (service line): This is typically the homeowner’s responsibility from the meter to the house. Call Kenowa Plumbing for service line inspection and repair — we handle underground line work.
Leak Repair Cost Estimates for West Michigan (2026)
| Repair Type | Typical Cost Range (2026) |
|---|---|
| Running toilet repair (flapper/fill valve) | $75 – $175 |
| Dripping faucet repair | $85 – $200 depending on fixture type |
| Supply line replacement under sink | $100 – $200 |
| Outdoor hose bib repair/replacement | $150 – $350 |
| Professional leak detection service | $150 – $400 depending on scope |
| Wall pipe repair (after location confirmed) | $250 – $800 depending on access |
| Slab leak repair | $500 – $3,000+ depending on method and length |
| Underground service line repair/replacement | $1,000 – $5,000+ depending on length and depth |
Frequently Asked Questions
Grand Rapids Water Utilities has a leak adjustment policy. If you can provide documentation of a confirmed repair, you may qualify for a one-time credit on an abnormally high bill. Call their customer service line or visit grandrapidsmi.gov to initiate a request. Your plumber can provide a repair receipt as documentation.
Running water sounds with nothing visibly on are a reliable sign of a hidden leak — most often a running toilet you can’t hear clearly, or a slab leak. Start with the toilet dye test, then call Kenowa Plumbing if the sound persists. Do not ignore it — even small continuous leaks cause significant water damage over time.
Yes — hidden leaks behind walls or under floors create the sustained moisture that mold needs to grow. Michigan’s humidity levels in spring and summer accelerate this. If a hidden leak has been present for weeks or months before discovery, mold remediation may be required alongside the plumbing repair. Kenowa Plumbing will flag this concern during the repair assessment.
It depends on your policy and the cause of the leak. Sudden and accidental damage (e.g., a pipe bursting) is typically covered. Gradual leaks or maintenance failures are often excluded. Detection costs may or may not be covered. Always document the leak and the repair thoroughly and contact your insurance provider before beginning major repair work.
