The question is not what the seal costs, but what it costs per year. A Green Drain™ for a standard floor drain is €39.99 including VAT. The manufacturer states a service life of five years or more, with no maintenance, no water and no electricity. That works out at about €8 a year, or €0.67 a month, per drain.
Comparing that with household remedies is not a comparison of price but of outcome. Bicarbonate and vinegar cost almost nothing, but they do not restore the water barrier — so the cost repeats every time the smell comes back, and the cause stays where it was.
How many drains actually need one
Not every drain. A seal earns its place where the drain is not used daily, because that is exactly where the trap water evaporates:
- Bathroom floor drain — almost always dries out, because little passes through it.
- Guest bathroom or second WC — used occasionally, an obvious candidate.
- Utility room, basement, garage, plant room — months without water.
- A shower used only now and then — in a house with several bathrooms.
A shower and a sink in daily use rarely have the problem; the water replenishes itself. A typical flat therefore needs one or two, a house two to four.
A flat with one floor drain: €39.99 once, about €0.67 a month over five years. A house with three drains: €119.97, or roughly €2 a month for the whole property.
What is really being compared
Most people are not choosing between a seal and nothing. They are choosing between a seal and something they already do:
| Approach | Cost | Does it address the cause |
|---|---|---|
| Bicarbonate and vinegar, boiling water | Negligible, but repeats | No — does not restore the water barrier |
| Chemical drain cleaner | Per bottle, repeatedly | No — and over time it damages seals and pipework |
| Scented gel or air freshener | Monthly, indefinitely | No — masks the smell |
| Topping the trap up with water | Free | Partly — only while someone remembers |
| Calling a plumber | Call-out plus labour | Depends on the cause; a dry trap is nothing to repair |
| Passive silicone seal | €39.99 per drain, five years or more | Yes — replaces the water barrier with a mechanical one |
The last row is the only one where the spending stops. The others repeat for as long as the drain exists.
Why there is no cheaper version
The question comes up often, so here is the direct answer: the membrane is medical-grade silicone tested to 2,500 cycles under ASSE 1072-2020 and from −40 °C to +100 °C. A membrane that stiffens after two years and stops sealing would not be cheaper — it would be free for a year and a problem in the second. Prices are public and the same for everyone, published in our price list.
How far the seal reaches
The seal closes the pipe, so it stops everything coming from below — sewer gases, odour and aerosol from biofilm in the pipe beneath it, drain flies climbing up. What is in the pipe below the seal does not matter; what matters is that the passage is shut.
Only what sits above the membrane stays outside the barrier:
- Deposits above the membrane — on the grate, in the drain throat and in the short section of pipe above the seal. That is in the room rather than behind the barrier, so it still needs cleaning by hand.
- A blockage — the water does not drain. That is a flow problem, not an odour one, and it needs clearing.
- A cracked pipe or poor installation — a job for a plumber.
- Another outlet — if the smell is coming from the sink or the shower, a seal in the floor drain does not touch it.
A simple check: with the seal fitted, if the smell persists, the source is above the membrane — the grate and the drain throat — or another drain in the room.
Working it out for your own case
- Count the drains that are not used daily.
- Measure the internal diameter of the pipe below the grate — not the grate, not the bowl.
- Multiply the number of drains by the price of the size you need.
- Divide by five for the annual figure.
Sizes and prices are in the catalogue, and if you are unsure about the diameter there is a measuring tag. When in doubt, take the smaller size — the silicone ribs expand.