Most toilet faults come down to three parts and one seal. A toilet that runs is a failed flapper, flush valve or fill valve. A toilet that rocks or weeps at the floor is a failed wax seal or a broken closet flange underneath it. A toilet that drips at the wall is the supply line or the shut-off valve. A minor rebuild renews the working parts in the tank; a major rebuild adds the tank-to-bowl bolts, flush handle, supply line and cut-off valve. Replacement is for a cracked bowl or a fixture past saving.
Why a toilet keeps running
A toilet that will not stop running is the most common call on this list, and the tank tells you why within about a minute of the lid coming off.
- The flapper or flush valve is not sealing
- Water creeps from the tank into the bowl, the level drops, and the fill valve keeps topping it up. This is the classic phantom refill that runs all night and shows up on the bill.
- The fill valve has failed
- Either it never shuts off, or it will not open properly and the tank fills slowly or not at all. One call we took was a toilet that simply would not fill; a failed fill valve was part of it.
- Debris is holding a seal open
- We have found a floater loose in a tank — grit and black gasket fragments circulating from elsewhere in the system — and a separate toilet that would not fill because of debris in the line. When black rubber fragments show up in more than one fixture, the supply side is shedding them and that gets investigated too.
- The tank-to-bowl bolts are going
- Deteriorating bolts weep between tank and bowl and are one of the things that turns a minor rebuild into a major one.
- The flush handle and lever are worn
- Cheap to put right, and often replaced at the same time. We have fitted owner-supplied flush handles as part of a wider visit.
None of this needs a new toilet. It needs the right parts and somebody who will also look at why they failed.
Minor toilet rebuild or major toilet rebuild — what is the difference?
Both terms appear all through our contract record, and they mean specific things rather than small and large.
| Minor rebuild | Major rebuild | |
|---|---|---|
| What is renewed | The working internals of the tank — fill and flush components — so the toilet flushes and seals properly again. | The internals plus the overflow, the tank-to-bowl bolts, the fill valve, the flush handle, the supply line and usually the shut-off valve. |
| When we recommend it | The fixture is sound, the shut-off holds, and only the tank parts have worn out. | The bolts are corroding, the shut-off will not close, or the toilet has been limping for years and the parts are all of an age. |
| What we check either way | That the shut-off valve actually shuts off before anything is opened up. | House water pressure, because a failed PRV is what takes out valves and supply lines in the first place. |
A first-floor toilet that would not stop running came to us as a running-toilet call. What we found was deteriorating tank-to-bowl bolts along with the valve, the supply line and the flush handle — a major rebuild, not a flapper. Shutting the water off to do it then turned up the original pressure reducing valve still in place, a leaking cut-off valve to the outside faucet, and rust on the water heater.
Why a toilet leaks at the base or rocks on the floor
Water at the base is not a tank problem. Something under the fixture has failed, and it is usually one of two things:
- The wax seal has failed. On more than one call we pulled a toilet and found the wax seal gone, water passing straight through to the floor below — in two of those, the damage was already showing in the basement ceiling before anyone realized the toilet was the source.
- The closet flange is broken, bent, rusted or rotted. We have pulled toilets off flanges bent out of shape, flanges rusted out with both closet bolts stripped, and a flange rotted away on both sides so the fixture was sitting on nothing.
- The flange is set below the finished floor. One toilet was sitting on a flange left low by a previous contractor’s tile installation. The fixture sat raised, the seal never made up properly, and sewer gas was getting into the house.
A rocking toilet is the warning shot. Every flush works the seal, and once it passes water the subfloor goes soft. On one job the water had traveled under the linoleum from one side of the bathroom to the other before anyone saw it, and the subfloor had to be replaced and waterproof board installed before a new fixture went down.
Toilet flange and wax seal repair
Resetting a toilet correctly is a short job done properly and an expensive one done badly. The sequence we work to:
- Shut off and disconnect, drain the tank and bowl, and lift the fixture clear.
- Inspect the flange itself — not just the seal. A flange that is cracked, rusted, bent or sitting low is why the seal failed.
- Repair or replace the flange. We use slip-in repair flanges and spanner repair flanges depending on what is left of the original, and we bring the flange up to finished floor height where a floor covering has buried it.
- Check the subfloor around the opening. If it is soft, it gets cut out and replaced before anything is reset.
- Reset the fixture on a new wax seal with new closet bolts, and fit a new supply line and shut-off valve while the fixture is out of the way.
- Re-caulk the base, removing the old caulk as thoroughly as the floor allows.
If the toilet is also backing up, the flange is only half the story — see clogged toilet repair, because a fixture that clogs repeatedly is often reporting a problem further down the line.
When a toilet is worth replacing instead of rebuilding
We would rather rebuild. Parts are quicker and less disruptive than a new fixture, and a sound bowl can outlast several sets of internals. These are the cases where we say replace instead:
- The bowl or tank is cracked. One corner toilet had cracked on both the right and left sides. Pulling it showed the flange rotted out on both sides, leaving the fixture unsupported — almost certainly what broke it.
- The fixture has lost its flush. Where a toilet still will not flush properly after the fixture and the line have both been cleared, the toilet itself is finished.
- It is old and failing repeatedly. A fixture at least ten years old that kept backing up was replaced with an elongated commode with a soft-closing seat rather than rebuilt again.
- It is a one-piece fixture that has to come off. One-piece toilets can crack when they are pulled. We tell homeowners that before we lift one, because it changes the decision.
- You want the height changed. Standard bowls are replaced with comfort-height fixtures routinely, and we have fitted comfort-height toilets with grab bars where accessibility was the point of the job.
What a new toilet installation includes
A toilet installation is never just the fixture. On our jobs it takes in everything the fixture depends on:
- The old toilet removed and hauled away, and old caulk taken off the floor as completely as the surface allows.
- A new wax seal and new closet bolts every time — old bolts are stripped or corroded more often than not.
- A new toilet supply line, normally a metal braided line, and a new shut-off valve. These two items appear on almost every toilet job in our record for a reason.
- The closet flange inspected, repaired or replaced, and set at the right height relative to the finished floor.
- A new P-trap and drain connection where the fixture is being installed somewhere new rather than swapped in place.
- The fixture leveled, seated, secured and re-caulked at the base.
Where a toilet is going into a bathroom that is being rebuilt around it, the same work happens inside a larger job — see bathroom remodeling for how that runs, and bathroom sink repair and installation for the vanity side of the room.
Can you install a toilet I bought myself?
Yes. Owner-supplied fixtures are common in our record — we have installed owner-provided toilets in pairs with new supply lines and valves as part of wider punch lists, and fitted owner-supplied flush handles and seats.
Two things are worth knowing before you buy. First, rough-in distance and bowl shape have to match the opening you already have; an elongated bowl in a tight powder room is a problem you only discover once the old one is out. Second, if the fixture arrives damaged or the parts in the box are wrong, that is between you and the retailer — which is why some homeowners would rather we supply the fixture and stand behind the whole installation.
Either way the flange, the seal, the bolts, the supply line and the valve are ours, because those are the parts that leak.
Can a running toilet cause a high water bill?
Yes, and it is the first thing we test. High-bill calls are a recurring job type for us, and the process is systematic rather than a guess: every toilet in the house, every cut-off valve, every faucet, and the underground service line to rule out a buried leak.
What those investigations actually turned up:
- One house had several toilets needing rebuilds, multiple failing cut-off valves, a couple of failing faucets, and electrolysis forming at the water heater connections.
- Another had a running toilet upstairs, washing machine valves and hoses needing replacement, and a saddle valve on the water heater line flagged as a leak risk — with outside testing still pointing at a possible underground leak.
- A third had three toilets checked, one broken and running, plus two separate leaks at a tankless water heater.
A running toilet is the cheapest thing on that list to fix and usually the largest share of the loss. If the bill stays high after the fixtures are sorted, the search moves to the service line — see pipe repair and leak detection.
Why toilet valves and supply lines keep failing in Northern Virginia
Because the house is running at the wrong pressure. Nearly every property on public water here has a pressure reducing valve at the service entry, and when it fails the whole house sees street pressure.
A homeowner called us about two toilets not running properly. Inspecting the fixtures and their shut-offs turned up many leaking cut-off valves through the house, and shutting the water off revealed the pressure reducing valve itself leaking. The toilets got a rebuild, a new cut-off valve and a new supply line each — but the PRV, a new main cut-off valve, an isolation valve, a pressure gauge and a bonding ground were the actual repair.
That is why a pressure gauge goes on the house as part of a toilet call. Fixing the fixture without fixing the pressure just schedules the next failure. See water pressure, PRVs and shut-off valves.
What toilet repair and installation costs
We do not quote toilet prices by phone and we do not publish them. A rebuild, a reset on a new flange, a flange repair with subfloor replacement underneath it and a full fixture replacement are four different jobs, and until the toilet is lifted nobody honestly knows which one is in front of them.
An estimator comes to the property, looks at the fixture, the flange, the valve and the floor, and gives you a written price before any work begins. Sam & Sons Services has worked across Northern Virginia since 1999 under Virginia DPOR license #2705070610.
