Heavy rain in Valencia: how to get your drains and downpipes ready

Quick answer. Before the rainy season, clean the drains on terraces and in courtyards, check that downpipes and gutters are not blocked and that drainage chambers drain properly. During a storm, if water comes back up through the drains on the lower floors, stop using washing machines and showers and tell the property manager. If people are at risk, follow Civil Protection instructions and call 112.

In Valencia we know it well: in autumn, as much rain can fall in one afternoon as falls in a month elsewhere. In those hours, every drain, downpipe and drainage chamber in the building has to take a huge amount of water at once. A handful of leaves on a terrace or a drainage chamber full of mud is enough for water to get into a home or come back up through a ground-floor shower. Most of these problems can be avoided with a half-hour check before it rains.

• Checklist before the rain
• Area by area: what can go wrong
• During the storm
• Afterwards: what to check

Checklist before the rain

• ☐ Terrace and balcony drains free of leaves, soil and plastic. Pour in a bucket of water and check it drains quickly.
• ☐ Roof gutters and downpipes free of blockages and loose joints.
• ☐ Drainage chambers in the courtyard and entrance free of mud and with the cover in place.
• ☐ Terrace pots and furniture moved away from the drains.
• ☐ Garages and basements: clean grates and, if there is a sump pump, check that it works.

Area by area: what can go wrong

Area	Typical fault	Prevention
Terrace or balcony	Blocked drain, water comes in under the door	Clean the drain and grate
Roof	Blocked gutter or downpipe overflowing down the facade	Check before autumn
Light well	Drain or drainage chamber overwhelmed, water on the ground floor	Clean drainage chamber and clear drain
Ground floor	Water coming back up through showers and drains	Check the sewer pipe and main drainage chamber
Garage or basement	Overwhelmed grates, water getting in	Clean the grates and check the pump

During the storm

1. If water comes back up through the drains, stop using washing machines, showers and toilets and ask the neighbours to do the same.
2. Switch off the electricity in flooded areas if you can do so without stepping in water.
3. Do not go down into garages or basements if water is coming in.
4. Follow official warnings and, if people are at risk, call 112.

Plumber's tip: safety comes first. No drain is worth anyone climbing onto a roof or going down into a basement during a storm. Whatever can't be done safely can wait until it has passed.

Afterwards: what to check

• New stains on ceilings and walls, especially on the top floors and next to downpipes.
• Drainage chambers with mud or debris washed in by the water.
• Drains that now empty more slowly or smell.
• Photos of the damage for the insurance, before cleaning up.

In a residential building, the most effective approach is to include this check in regular maintenance. If a main blockage appears after the rain, see our guide on the blocked downpipe.

Frequently asked questions

How often should drainage chambers and downpipes be checked?

At least before the rainy season and after heavy rain. A maintenance plan helps you not to forget.

Who is responsible in a residential building?

Main downpipes and drainage chambers are usually communal elements, so the association normally organises it through the property manager. Drains on private terraces are usually each owner's responsibility.