High Water Bill? A Plumber’s Guide to Common Causes

Overview

A sudden spike in your water bill can be frustrating and confusing. In many cases, the cause isn’t immediately visible. That’s why understanding the potential sources of hidden water waste is essential. As a seasoned plumbing company, Optimus Plumbing & Heating knows the most common reasons behind rising water bills and offers expert advice on how to detect and fix them.

Whether you’re a homeowner or a property manager, this blog post will help you recognize key plumbing issues that may be silently draining your budget.

Introduction

Opening your water bill and seeing a number that’s twice what you expected? You’re not alone. Unexpectedly high water bills are one of the most common concerns plumbers hear about, especially when there’s no obvious cause.

The good news: most causes of water waste can be identified and resolved quickly once you know what to look for. This guide breaks down the top culprits behind high water bills, how to spot them, and when to call in a professional for help.

Leaky Fixtures and Running Toilets

One of the simplest explanations is also the most common: leaks. A single dripping faucet can waste over 3,000 gallons per year, and a running toilet can drain even more.

The danger lies in how subtle these leaks can be. You may not hear them or see water pooling. But they continue to waste water 24/7.

Common signs include:

A toilet that makes a hissing or trickling sound
Damp or discolored areas around plumbing fixtures
Increased mold or mildew near water sources

Replacing a faulty flapper valve in a toilet or tightening a loose faucet connection can often resolve the issue quickly.

Hidden Pipe Leaks

Not all leaks are visible. Some occur behind walls, under floors, or beneath your home’s foundation. These are known as hidden or slab leaks and can be major contributors to spiking water bills.

Indicators of hidden leaks include:

Unexplained damp patches on floors or walls
Reduced water pressure
Warm spots on flooring (hot water line leaks)
A constantly running water meter even when all water is off

Since these leaks can cause structural damage and encourage mold growth, early detection is key. If you suspect one, don’t delay in contacting a plumber who can use specialized leak detection tools.

Outdoor Irrigation and Hose Bib Issues

Your outdoor plumbing may be quietly siphoning water without your knowledge. Automatic sprinkler systems are especially notorious for hidden leaks, particularly in older systems or those exposed to freezing temperatures.

Hose bibs (outdoor faucets) can also develop slow leaks that go unnoticed, especially if they drain into the soil.

Here’s what to check:

Water pooling in your yard when sprinklers are off
Unusual green patches of grass
Dripping hose spigots or broken backflow preventers

Even though irrigation systems are often installed by landscapers, diagnosing and repairing the water lines, valves, or hose bibs behind them is squarely within a plumber’s expertise. A licensed plumber can pinpoint underground leaks, replace damaged fittings, and ensure your outdoor water connections aren’t quietly driving up your utility bill.

These systems should be inspected regularly, particularly in spring after freezing temperatures can cause cracking.

Water Softeners and Filtration Systems

While not always the first suspect, whole-home water softeners and filtration systems can be hidden culprits behind rising water bills. These systems periodically flush water during their regeneration cycles. If something goes wrong—a stuck valve, a faulty sensor, or a misconfigured setting—they may continuously drain water without your knowledge.

Some warning signs include:

Frequent regeneration cycles
Water draining from the softener even when not in use
Salty or overly soft water

Why Can’t a Plumbing System Alone Prevent Hard Water Damage?

Though it may seem that a well-designed plumbing system should prevent issues, it doesn’t eliminate the effects of hard water. Minerals like calcium and magnesium can still build up in your pipes, appliances, and fixtures, which is why softeners and filtration systems are often necessary. When they function correctly, these systems extend the life of your plumbing by minimizing mineral buildup and improving water quality. But when they malfunction, they can cause ongoing water waste.

If you notice any of the above issues or suspect your system isn’t functioning properly, call a licensed plumber. They can inspect the system, diagnose the issue, and help you avoid long-term waste or damage.

Inefficient or Faulty Appliances

Water-using appliances like dishwashers, washing machines, and water heaters may have internal leaks or inefficiencies that add up over time.

For example, an old washing machine can use up to 40 gallons per load, compared to under 15 gallons for newer models. If the appliance develops a slow internal leak or doesn’t shut off properly, it could run unnoticed for hours.

If this happens (and it often does), you’re looking at a tremendous amount of wasted water and sky-high utility bills.

Watch for:

Damp areas near appliances
Water sounds when appliances aren’t in use
Unusually long or inefficient wash cycles

If your appliances are over a decade old, it may be worth upgrading to Energy Star-certified models that reduce water and energy use.

Water Pressure Problems and Aging Infrastructure

High water pressure might seem like a luxury, but it can actually cause premature wear and tear on your plumbing system. Excess pressure stresses joints, valves, and connections, increasing the likelihood of leaks and inefficiencies.

Older plumbing systems are particularly vulnerable. Galvanized steel pipes, common in mid-20th-century homes, corrode over time and are more prone to cracking or bursting. Homes built before the 1980s may be especially at risk if the original piping hasn’t been replaced.

To assess your water pressure, consider using a pressure gauge at an outdoor spigot. Residential pressure should fall between 40 and 60 psi. Anything above 80 psi is considered excessive and could warrant the installation of a pressure-reducing valve (PRV).

Alternatively, you can (and should) take the safer route by hiring a plumber with the expertise to handle it properly.

Seasonal and Behavioral Water Spikes

Not every water spike is caused by a plumbing issue. Sometimes, it’s just seasonal habits or changes in daily routines that drive up your usage.

In summer, for example, households often use more water to fill pools, water lawns, or run water-cooled air conditioning systems. You might also host more guests, which means more showers, dishes, and laundry.

Even something as simple as a houseguest who takes long showers or leaves a tap running can noticeably increase your monthly bill. If your usage jumps around the same time as a routine change, the reason could be more behavioral than mechanical.

To stay informed, keep an eye on seasonal trends and consider installing a smart water monitor. These devices provide real-time data and can alert you to unusual usage before it becomes a costly surprise.

Water Meter Test: A DIY Leak Check

Think you might have a leak but aren’t sure where it’s coming from? Before calling in a professional, you can run a quick check using your water meter to confirm if water is escaping your system. It’s simple, effective, and doesn’t require any tools.

Here’s a simple test to conduct:

Turn off all water sources in your home.
Record the current reading on your water meter.
Wait at least 2 hours without using any water.
Check the meter again.

If the meter reading has changed, it’s likely the case that you have a leak somewhere in the system. This test won’t tell you where the leak is, but it confirms whether there is one. At that point, a plumber can help pinpoint the source.

Tips for Reducing Water Usage

Now that you know the most common culprits behind a rising water bill, it’s time to take action. In addition to working with a local plumber to address any leaks or inefficiencies, there are simple lifestyle changes and upgrades that can make a big difference.

Want to lower your bill and save resources? Try these strategies:

Install low-flow toilets and aerated showerheads
Run dishwashers and washers only with full loads
Water lawns early or late to reduce evaporation
Collect rainwater for garden use
Fix leaks immediately
Educate family members on smart water habits

Check your local utility’s rebate programs for water-saving appliances and upgrades.

When Should You Call a Plumber for Plumbing Issues?

If you’ve completed a water meter test and checked for visible leaks but still can’t find the source of the problem, it’s time to call a licensed plumber. They have the tools and training to perform advanced diagnostics like acoustic or infrared leak detection, pressure regulator testing, and inspections behind walls or under your foundation.

Many plumbers offer emergency plumbing services, and sudden spikes in water bills often qualify as urgent plumbing issues. For trusted, responsive help during a water bill emergency, check out Optimus Plumbing & Heating’s emergency plumbing services.

Don’t Let Your Money Go Down the Drain—Work With a Plumber

A high water bill is a warning sign. Whether it’s a dripping faucet, a cracked pipe, or dated fixtures, the key is acting quickly before minor waste turns into major cost.

Optimus Plumbing & Heating is a seasoned plumber with the know-how to handle leaks of all kinds. From general concerns to emergency plumbing issues, call us at (240) 855-6342 to request a plumber to inspect your plumbing system.