What a running toilet adds to your bill

$467.24

added per 90-day bill by 200 gallons a day, our arithmetic

A running toilet cost about $467.24 extra per 90-day WSSC Water bill at 200 gallons a day on a 145-gallon-a-day house, by our arithmetic; a worn flapper at 30 gallons adds $57.46.

By the Your Water Numbers desk, not WSSC Water · Updated November 2, 2026 · How we check

Look up your number: leak size to extra dollars per 90-day bill

Leak, gal/day	145 gal/day house	80 gal/day house	Note
8	+$14.41	+$14.22	About a drip per second
25	+$46.56	+$44.85	About EPA’s average home leak
30	+$57.46	+$53.86	Worn flapper
50	+$101.08	+$89.90	9% of homes waste 50 or more
100	+$210.11	+$185.29	Tier 3 on the bigger house
200	+$467.24	+$405.63	Running toilet, older EPA figure
300	+$741.92	+$680.31	Top tier on both
500	+$1,291.28	+$1,229.67	Nearly all in the top tier
720	+$1,895.58	+$1,833.96	Fill valve stuck at 0.5 gpm

Source: Our arithmetic; leak sizes from EPA · FY27 rates, leak running the whole 90 days

Reading this: Pick your house’s normal use in the column head, then your leak size. A leak that ran only half the period costs less than half, because of the tiers.

Inside an emptied toilet tank, the plastic flapper on the flush valve with its chain and the overflow tube — Inside a toilet tank, with the flapper that seals the bottom.

How big is a typical toilet leak?

EPA’s figures run from about 30 to about 200 gallons a day, and higher for a stuck fill valve. Its leak device guide puts a worn flapper at about 30 gallons a day, almost 900 a month. An older EPA page puts a running toilet at about 200.

The same guide says about 20% of toilets leak, and a constantly running fill valve passes 0.5 to 3 gallons a minute, up to 4,300 gallons a day. Left running at that ceiling for 90 days, it would add about $11,700 (our arithmetic).

Why do larger leaks cost more per gallon?

Because they push your last slice into pricier rate tiers. A small leak on a 145-gallon house mostly pays $20.02 per 1,000 gallons. A big one reaches $30.52.

Each 1,000 leaked gallons costs more as the leak grows

$20.02

$22.46

$23.35

$25.96

$27.48

$28.70

8 gal50 gal100 gal200 gal300 gal500 gal

Source: Our arithmetic, leak dollars over leak gallons · 145 gal/day house, 90-day bill

What does leaving it for a year cost?

Multiply by four. A worn flapper comes to $229.84 a year on the 145-gallon house and a 200-gallon running toilet to $1,868.96 (our arithmetic).

Compare that with EPA’s advice to replace a flapper at least every five years. EPA says fixing leaks saves about 10%.

The same leak costs more on the house that already uses more

25 gal, 145 house$46.56

25 gal, 80 house$44.85

100 gal, 145 house$210.11

100 gal, 80 house$185.29

300 gal, 145 house$741.92

300 gal, 80 house$680.31

Source: Our arithmetic, both house sizes · extra per 90-day bill

Is your toilet the leak?

Run the dye test: color in the tank, no flushing, then look at the bowl. EPA waits 10 minutes and the WSSC Water billing guide waits 20. The fuller check, with the 2-hour meter reading, is on the high bill page.

What if the meter moves and toilets pass?

Then it may be elsewhere, including out of sight. Owners pay for what registers on the meter, and the line from the property line into the house is the owner’s.

Bring in a licensed plumber for hidden leaks. We could not confirm what homeowners may do themselves under the plumbing code, so ask WSSC Water’s plumbing inspections about anything beyond a tank part. If money is the barrier, CAP Leak Repair exists for those who qualify.

On tape: “WSSC Water: How to Check for Toilet Leaks Using Dye Tablets”, from the WSSC Water channel. It waits 15 minutes; EPA says 10 and the billing guide 20, so longer is fine. Not our video; nothing loads from YouTube until you press play. The still comes from a copy on this site.

What to do with this number

Dye-test every toilet in the house this week
Read the meter before and after 2 hours of no use
Look up your leak size above and compare it with your bill’s jump
Swap a flapper that has passed five years

Questions on this page

Does a toilet leak on an upstairs bathroom cost the same as one in the basement?

Yes. The meter only counts gallons, so the location changes nothing on the bill.

Why is the extra smaller on the 80-gallon house?

It starts lower in the tier table, so more of the leak is priced at the cheaper rates.

How much of a winter bill might be a leak?

EPA’s flag is a family of four above 12,000 gallons in a winter month, or 400 a day by our arithmetic.

Can I get money back for a leak I fixed?

Owners pay for water that registers, but the high bill page above sets out the adjustment line and its terms.

Where each number comes from

Figure	What it is	Source	As of
About 30 gal/day; 0.5–3 gpm; 4,300 gal/day; 20%	Flapper and fill valve flows, share of toilets leaking	EPA WaterSense leak device guide	Feb. 2026
About 200 gal/day	Running toilet, older figure	Archived EPA fix-a-leak page	2017 snapshot
9,300 gal; 9%; 3,000 gal; 10%; five years; 12,000 gal	Leak rates and flapper advice	EPA, Fix a Leak	as read Nov. 2026
Owners pay for registered water	Billing rule, linked in the text	WSSC Water billing adjustments	see that page
All dollar rows	Added cost per 90-day bill	Our arithmetic from WSSC rates	leak table rows