First-time homeowner learns true cost of sprinkler system after getting 105,000-gallon water bill

A new homeowner was astonished by their first full water bill for a recently purchased house: 105,000 gallons over four weeks, averaging about 3,500 gallons per day.

That figure seemed even harder to explain because the homeowner said the property had no pool and nothing obvious, such as soggy ground or another clear sign; they feared a major leak.

Here's what to know

After getting that first complete bill, the homeowner went to Reddit for help, writing, "I literally don't understand where this water is going," explaining in the Reddit thread that the house had a seven-zone irrigation system set to run daily for 15 minutes per zone.

Commenters picked up on the irrigation system and said the watering schedule alone could reasonably account for the huge total. As one commenter put it: "15 minutes x 7 zones x 7 days = 12 1/2 hours each week of a tap being wide open! That's 50 hours a month."

One self-described water utility worker identified irrigation and toilet leaks as the two most common causes of unusually high usage. That commenter added, "Yes, you can use 105k on irrigation in a month, we see that all the time."

The homeowner added an update. They shared that after shutting off the sprinkler system on Sept. 16, the house still used about 57,000 gallons over a 40-day span beginning Sept. 1—or roughly 1,425 gallons a day.

More background

In the post, they suggested they may have inherited an irrigation setup without realizing how much water it could consume.

A commenter estimating flow from a 0.75-inch meter said one irrigation zone might run at around 13 to 15 gallons per minute, which would put seven zones near 1,500 gallons a day. The same commenter said daily use could reach about 3,000 gallons if both A and B controller programs were running.

One commenter put some focus on other potential issues. They said a similar spike turned out to be a leak in the supply line between the street and the house, while another described a rental where water had been running unnoticed through the garage floor.

Another commenter summed up the financial risk, describing a leak as "an easy plumbing fix and thousands of $ to pay for the wasted water." 

What can be done?

Checking the meter is a key troubleshooting step. Commenters advised shutting off all water, keeping the sprinkler system off, and tracking the meter either hour by hour or over at least a full day when no one was home.

Others recommended testing the irrigation system one zone at a time. One suggestion included manually running each sprinkler zone for 15 minutes, then checking the meter after each one to identify which zone used the most water and whether a leak might be hidden there.

To check for toilet leaks, the utility worker suggested putting food coloring in the tanks, waiting 15 minutes, and seeing whether any color appears in the bowl to see if a flapper or valve might be leaking. 

The thread also noted that utilities may offer additional help: "many offer bill adjustment programs if you find and fix the problem," while another user said some water companies offer leak forgiveness and "you can get some of your money back."

A self-identified water utility worker wrote: "The top two high use causes are irrigation and toilet leaks (where the water leaks from the tank into the bowl and out of the property, often unnoticed)."

Where can I learn more?

These stories cover similar water-bill surprises, leak checks, and irrigation choices. They include a costly California bill, a simple toilet-leak test, and several ways to reduce outdoor water use.

• In California, a homeowner slashed water use after a $637 bill, then hit summer pricing.

• A realtor showed homeowners how food coloring can expose a silent toilet leak.

• One gardener built easy DIY drip irrigation from recycled bottles to curb outdoor watering.

• Gardeners used a simple garden watering hack to keep plants alive with less water.

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