How much water should be in a floor drain?

Enough to fill the bend, which you cannot see from above. In practice: pour water in until it stops disappearing. If it keeps draining away no matter how much you add, the trap is not holding and that is worth a plumber.

Can I pour water down my basement drain?

Yes, and for a drain that has gone dry it is exactly the right thing to do. Plain water is all it needs.

There is water in the drain but the basement still smells. What now?

Then the seal is doing its job and the smell is coming from somewhere else — a dry trap on another fixture, a crack in the stack, or damp in the structure. The last one is the one this site can help with.

Does a floor drain connect to the perimeter drain?

It should not. The Appeal Board ruling quoted above is about exactly this separation. Older houses were sometimes plumbed before it was settled, so a connection existing is not proof it is correct.

There is water sitting in the floor drain in my basement. Is that normal, or is something wrong?

Should there be water in my basement floor drain?

Direct answer · reviewed 2026-10-13

Yes, there should be water in it, and seeing it is good news. A floor drain has a U-bend under it that holds a little water on purpose, and that water is the only thing standing between your basement and the sewer. Drains in rooms nobody uses dry out over a summer, and the first sign is a smell. The problem to worry about is the opposite one: water coming up out of the drain rather than sitting in it. That is a backup, it is the sewer side of the house, and it is not your perimeter drain — two different systems that get confused constantly, with different trades, different costs, and a different answer about who pays.

Conditions and exceptions

If you can smell sewer in a basement, do not start with the drains outside. Pour a few litres of water down every floor drain first and see whether the smell goes.
Water rising out of a floor drain during heavy rain, with no blockage, usually means the sewer itself is surcharged. That is a municipal conversation, not a plumbing one.
Nothing on this page is a diagnosis. Which pipe is at fault is settled by looking inside it.

Drain problem assessment

Local evidence

Every figure below is quoted from the source shown or is our labelled estimate. Verified dates are the day we last checked the source; a figure whose check is overdue is withheld rather than shown.

May roof or driveway water be put into the perimeter drain?: No — the Building Code Appeal Board has held that foundation perimeter drains are perforated subsoil drainage pipes which cannot form part of a storm drainage system, and that area drains must instead be connected to the storm sewer with approved solid pipe; The ruling concerned driveway area drains; the same reasoning is why roof water does not belong in the perforated pipe either · Older houses were often plumbed before this was settled, so an existing connection is common and is not evidence that it is correct; Building Code Appeal Board, Province of British Columbia · quoted · verified 2026-09-22
What Saanich tells a homeowner to do when a drain backs up: Call a plumber to find where the blockage is — and if it turns out to be on municipal property, notify Saanich Public Works immediately and have the plumber stay on site; Other municipalities run their own process — this is Saanich's own wording, not a regional rule · The page does not state who is liable, and nothing here should be read as saying the municipality pays; District of Saanich · quoted · verified 2026-10-13
Is water that comes in from outside covered as standard?: No. Sewer backup, overland water and groundwater seepage are each optional, bought separately, and none is in a standard policy; Wording differs between insurers — your own policy is what decides a claim, not a summary; Insurance Bureau of Canada · quoted · verified 2026-09-22
Where a foundation drain is allowed to discharge: To a sewer, a drainage ditch or a dry well; A dry well may be used only where the natural groundwater level is below the bottom of the dry well, and must be at least 5 m from the foundation (Sentences 9.14.5.3.(1) and (2)); Province of British Columbia (BC Codes) · quoted · verified 2026-09-22

The water is the working part

Under the grate there is a U-bend, and it stays full. That trapped water is a seal: sewer gas comes up the pipe, reaches the water, and stops. Every fixture in the house has one — you can see the same bend under a sink. A floor drain is just the one nobody runs water into.

Which is why basement floor drains go dry. A laundry room drain gets topped up every wash; a drain in the corner of a storage room evaporates over a few warm months and then there is nothing between the room and the sewer. The symptom is a smell that comes and goes, is worse in warm weather, and has no visible source.

The fix costs nothing. Pour a few litres of water down it. If the smell goes, that was it, and the drain will need the same treatment every few months — some people keep a jug by the washer for exactly this.

Water coming up is a different question entirely

If water appears out of the drain, nothing above applies. The pipe is carrying water the wrong way, which means either a blockage downstream of you, or a sewer that is full and has nowhere to put what it is being given.

The step that matters is the one homeowners skip, because it can only be done on the day. Call a plumber to find where the blockage is — and if it turns out to be on municipal property, notify Saanich Public Works immediately and have the plumber stay on site

Where the blockage sits decides everything that follows, and it stops being provable the moment the plumber leaves and the line is cleared. Saanich's page lists tree roots, pipe problems, storms, vandalism and debris as the usual causes; it does not say the District pays, and neither do we.

Why this is not your perimeter drain

The two get confused because both are called drains and both are associated with wet basements, but they are not connected and are not supposed to be. No — the Building Code Appeal Board has held that foundation perimeter drains are perforated subsoil drainage pipes which cannot form part of a storm drainage system, and that area drains must instead be connected to the storm sewer with approved solid pipe

In plain terms: the floor drain is a plumbing fixture inside the house that runs to the sewer. The perimeter drain is a perforated pipe buried outside at the bottom of the foundation wall, collecting groundwater from the soil. To a sewer, a drainage ditch or a dry well

So the floor drain backs up from the inside, with water that was already in a pipe. A failed perimeter drain shows up differently — water at the base of a wall, a damp floor edge, a wet crawl space after days of rain rather than during one storm. Telling them apart on the first morning is most of the job, because it decides whether you are calling a plumber or an excavator.

And why it decides whether insurance is even in play

This is the practical reason to get it right before you phone anyone. No. Sewer backup, overland water and groundwater seepage are each optional, bought separately, and none is in a standard policy

A sewer backup is the one of those three that a lot of households actually hold, because it is the cheapest and most commonly offered. Groundwater arriving through a failed perimeter drain is a different purchase again, and the pipe itself is never the insured item under any of them.

Which means the same wet basement floor can be a claim or not a claim depending on which pipe put the water there. Photograph it before anything is dried out, whichever it turns out to be.

Questions homeowners ask

How much water should be in a floor drain?: Enough to fill the bend, which you cannot see from above. In practice: pour water in until it stops disappearing. If it keeps draining away no matter how much you add, the trap is not holding and that is worth a plumber.
Can I pour water down my basement drain?: Yes, and for a drain that has gone dry it is exactly the right thing to do. Plain water is all it needs.
There is water in the drain but the basement still smells. What now?: Then the seal is doing its job and the smell is coming from somewhere else — a dry trap on another fixture, a crack in the stack, or damp in the structure. The last one is the one this site can help with.
Does a floor drain connect to the perimeter drain?: It should not. The Appeal Board ruling quoted above is about exactly this separation. Older houses were sometimes plumbed before it was settled, so a connection existing is not proof it is correct.

Your next step

A plumber and an excavator fix different problems, and the wrong first phone call costs a visit.

Work out which system is wrong

📞 Call 24/7 💬 Text

Sources

Sewer and drain backups — what to do and who to call — District of Saanich, accessed 2026-10-13
BCAB #1226 — Area drains (18 December 1990) — Building Code Appeal Board, Province of British Columbia, accessed 2026-09-22
Flooding and insurance — what home insurance covers and what is optional — Insurance Bureau of Canada, accessed 2026-10-06
British Columbia Building Code 2018, Division B, Section 9.14 — Drainage — Province of British Columbia (BC Codes), accessed 2026-09-22

Code and municipal requirements are quoted from the sources above; price ranges are what named local companies publish, and the companies that publish them sell the work. Nothing here is a diagnosis of a particular house: only a camera in your own drain can tell you what is wrong with it. Report a correction.