Quick answer. If water comes up through the drains on the lower floors or several neighbours hear gurgling at the same time, the blockage is almost certainly in the downpipe. Ask everyone not to use washing machines or showers and tell the property manager. The main downpipe is usually a communal element, so the association normally pays; if a specific neighbour caused the blockage, the association can claim the cost from them.
A blocked downpipe is one of the most unpleasant faults in a residential building: it affects everyone at once, the ground-floor neighbour suffers most and it almost always happens at the worst moment, on a Sunday afternoon with every washing machine running. The good news is that it is easy to recognise and quick to fix if you act in the right order.
- How to tell if the blockage is in the downpipe
- What to do while the plumber is on the way
- Who pays for the unblocking and the damage
- A schedule so it doesn't happen again
How to tell if the blockage is in the downpipe
| What happens | Where the blockage is |
|---|---|
| Only your sink or shower drains badly | In your own drain |
| Water comes out of the ground-floor shower or tray when other neighbours use water | In the downpipe or sewer pipe, below that floor |
| Gurgling and smells in several homes at once | In the downpipe or its ventilation |
| The courtyard or entrance drainage chamber overflows | In the sewer pipe or main drainage chamber |
What to do while the plumber is on the way
- Spread the word in the building: no washing machines, dishwashers, showers or flushing until it is sorted. A message in the neighbours' group chat works.
- Tell the property manager or the president: this is a fault affecting the whole building.
- Protect the ground-floor home: covering the shower drain with a plug and something heavy helps stop water coming back up.
- Don't pour caustic soda or chemical drain cleaners into a main downpipe: they don't reach the blockage and can damage old pipes.
- Take photos of the damage for the building's insurance.
What blocks a downpipe most
- Wet wipes, even those labelled “flushable”: they don't break down like paper.
- Cooking oil and grease, which solidify and trap everything else.
- Building debris: plaster, cement or paint poured down the toilet during renovation work.
- Cotton buds, hair and sanitary towels.
Who pays for the unblocking and the damage
The building's main downpipe is usually considered a communal element and the association is obliged to maintain it. So the usual arrangement is for the association to pay for the unblocking and repair, and for its insurance to cover the damage in the homes.
Two common exceptions: if it is shown that a specific neighbour caused the blockage (building debris, for example), the association can claim the cost from them. And the branch pipe connecting each home to the downpipe is usually treated as a private installation, although this depends on the association's rules and on the case.
Plumber's tip: if blockages happen every few months, the problem is not just what gets flushed. There is usually too little fall, a displaced joint or a very old downpipe. Unblocking again and again costs more than having it inspected properly once.
A schedule so it doesn't happen again
| When | What to do |
|---|---|
| Always | Notice in the entrance: what not to put down the toilet and sink |
| Before autumn | Check drainage chambers, drains and rainwater downpipes before heavy rain |
| During renovation work | Ask the contractor not to pour building debris down the drains |
| Every year | Inspection of the drainage system as part of a maintenance plan |
A maintenance for residential buildings helps spot these problems before the next emergency. Before the rainy season, also see our guide on how to get drainage chambers and downpipes ready.
Frequently asked questions
Can any neighbour call the plumber?
In an emergency, yes. Afterwards it is best to inform the property manager so the association can deal with payment and, if applicable, the insurance.
Does the whole downpipe have to be replaced?
Not necessarily. It depends on its condition, the material and whether the blockages keep coming back. If it is made of fibre cement and asbestos is suspected, it must not be cut or handled without following the applicable regulations.
Blocked downpipe in your building?
We unblock downpipes, sewer pipes and drainage chambers in Valencia and nearby towns, and prepare the quote for the owners' meeting.
This guide is for guidance only and does not constitute legal or insurance advice. Related: drain smell at home · leak from the upstairs neighbour.