Why is my sewer bill so high?

The City of Phoenix says its sewer fee is for sewer service and is based on the customer's average monthly water usage billed during the preceding January, February and March, typically the lowest water use months. In other words, the sewer fee is not a measurement of what you sent down the drain last month. It is an estimate set from your winter water use and applied to the months that follow.

That design has two effects:

• Winter is your sewer year. Whatever your meter recorded in January, February and March sets the sewer number, so those three months matter more than any other.
• A high winter can stay with you. If those months were unusually high because of a leak, guests, a filled pool or a burst of winter watering, the sewer fee can carry that inflated number forward.

Reading the water side of the bill helps you see the pattern. Phoenix says 748 gallons equals one billing unit, and that the water base fee includes 5 units (3,740 gallons) from October through May and 8 units (5,984 gallons) from June through September. So when you look at the usage history, convert gallons to units and compare winter months to each other. A winter month that runs several units above the rest is your first clue.

The sewer fee is also only one line on the bill. Phoenix lists several: a water base fee, a water usage fee, environmental mandates for water and wastewater, a city services tax, state-mandated jail costs, and state and other taxes that include stormwater fees. Some of these are based on meter size. Before you decide the sewer fee is the problem, read each line. Our how to read your Phoenix water and sewer bill page explains them.

Winter is normally the lowest-use period, so a high reading stands out. Common causes include:

• A leak. EPA says the average household's leaks can waste more than 9,300 gallons a year, and that nine percent of homes have leaks that waste 50 gallons or more per day. A leak that runs all winter is exactly the kind of thing that sets a high sewer number.
• A running toilet. EPA says an old or worn flapper can cause a toilet to flush on its own or silently leak thousands of gallons a year. See how to fix a running toilet.
• Outdoor use through the same meter. EPA says outdoor water use is more than 30 percent of household use on average and can reach 60 percent in arid regions. If a sprinkler system or hose runs in winter, that water is on the same meter as the water you use indoors. Because the city bases the fee on your average monthly water usage in those months, winter watering can raise it as well. If your yard has a separate irrigation meter, the picture is different. Ask the city how your account is set up.
• More people at home. A new baby, a relative staying for the winter or a rental unit changes indoor use. This is a real use of the sewer, so a higher fee follows.

EPA gives a benchmark you can use. It suggests looking at your water use in a colder month such as January or February, and says that if a family of four exceeds 12,000 gallons per month, there could be serious leaks. Phoenix bills show a 13-month usage history in gallons, so you can look back and compare.

Start with the meter. EPA says to check your water meter before and after a two-hour period when no water is being used, and that if the meter changes at all, you probably have a leak. Our water meter leak test page has a step-by-step version.

Then test the toilets. EPA says to put a few drops of food coloring in the tank, and if any color shows up in the bowl after 10 minutes, you have a leak. Flush right after so the dye does not stain the tank. EPA says worn flappers should be replaced at least every five years.

Then check the places you do not see. The City of Phoenix says the average household loses more than 10,000 gallons of water each year through leaks. Hidden leaks in walls, slabs or yard lines show up as meter movement with everything off. Our high water bill with no visible leak page explains the next steps.

Fixing a leak lowers your usage going forward. It does not undo the winter reading that set your sewer fee this year, so the timing of the fix matters. That is why the next section is worth a phone call.

Yes, and there is a formal process for it, with a deadline. The City of Phoenix says a Sewer Fee Review adjusts your sewer fee when water use was higher than usual, for example when a customer empties and refills a pool for cleaning, or when a spike is caused by broken plumbing or outdoor irrigation equipment. A winter leak that you have since fixed is exactly the kind of case it describes.

Know the rules before you start:

• The window. The city says requests received more than 60 days after the July bill date are not eligible for review, and that under Phoenix City Code 28-35 exceptions will not be granted. It also says requests may be submitted before the July billing period.
• The year. The city says the review covers the January, February and March billing cycle of the current year, and that sewer adjustments cannot be made for prior years. Do not wait until next year to raise this year's fee.
• The channel. The city's preferred route is the Sewer Fee Review section of myPHX311. If you cannot use the online system, the city offers a form you can download and submit by mail.
• The paperwork. Attachments must be in a non-editable format such as PDF. The city says photographs or screen captures of documents are not acceptable. So save your repair invoice and any meter-reading records as PDF documents, and do not send phone photos.

Phoenix Customer Services is the one-stop for water, sewer, trash and recycling questions, so call if you are unsure whether your case fits. If money is the problem, the city also lists help. Our help for a high water bill in Arizona page covers Project Assist and other resources.

Keep a simple log. Each month, write down the usage number from your bill and note anything unusual, such as guests, a new appliance or a repair. After a year you will have a record that makes every future question easier, including the one you might ask the city. A log also shows you whether a repair worked, because a leak fix should show up as a drop in the next reading.

Two steps help the next winter. First, get your yearly leak check done in the fall, before January. Second, watch your winter water use on purpose. If you must water in winter, know that it may land on the same meter that sets your sewer fee. For more savings ideas, see the best ways to reduce a water bill in Phoenix.

A separate point: a sewer bill is a charge from the city, and it has nothing to do with the condition of the sewer line at your house. A clogged or cracked line does not raise the fee. It causes backups, which are a plumbing problem, and you can read about them on our main line vs branch clog page.

If a leak turns out to be behind your bill, HQ Plumbing & Air is licensed and insured, gives free estimates and upfront pricing, and answers 24/7.