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ALPHA Gruppe AG I Dämmung und Brandschutz
5(3)
Reinacherstrasse 1014053 Basel
Laying & cleaning drainage pipes: Costs & Guide 2026
October 5, 2026
4 Minuten
Drainage pipes are essential for protecting your home against moisture. They intercept underground water and divert it away from the foundation. As of 2026, strict regulations apply in Switzerland regarding water infiltration and permits. Find out what you need to consider when planning, laying, and maintaining a drainage system.
Key figures and facts
The most important facts about planning and maintaining drainage systems at a glance.
- Gradient
- A drainage pipe requires a gradient of 0.5 to 1% so that the water can drain away reliably.
- Permit requirement
- Seepage water is considered extraneous water. Discharging it into the public sewage system is only permitted in Switzerland with a special exemption.
- Maintenance interval
- To prevent blockages caused by mud or limescale, the pipe should be professionally flushed every 1 to 3 years.
- Installation depth
- The pipes are installed at the level of the foundation and must never be higher than the basement floor.
- Lifespan
- Professionally laid drainage pipes made of plastic, concrete, or vitrified clay have a lifespan of 50 to 100 years.
These basic rules will help you avoid expensive water damage to the building.
Important technical terms
Drainage pipe
A pipe with small holes that absorbs water from the ground and drains it away.
Stormwater pipe
A closed pipe that transports surface and rainwater (e.g., from the roof) away.
Extraneous water
Unpolluted wastewater (such as seepage or spring water) that should not enter the sanitary sewer system to avoid overloading sewage treatment plants.
Flushing port
An accessible connection on the pipe system used for regular cleaning and pressure flushing.
Correctly distinguishing between these terms is important for communicating with authorities and tradespeople.
Disposing of seepage water: Infiltration vs. sewage system
Infiltration on your own property
Best suited when
the soil is sufficiently permeable and there is enough space available on the property.
Costs / Time required
Higher initial construction costs for the soakaway, but no recurring wastewater fees for extraneous water.
Risks / Disadvantages
During extreme heavy rainfall events, the absorption capacity of the soil can be exhausted.
Who should do it
Must be planned and implemented by a specialist civil engineering company.
Connection to the sewage system
Best suited when
infiltration on your own property is geologically or technically impossible.
Costs / Time required
Strict official review processes and potentially high recurring fees.
Risks / Disadvantages
Only approved by Swiss authorities in absolute exceptional cases.
Who should do it
Requires an official application by a specialist to the responsible municipality.
Laying a drainage pipe: The most important phases
Installing a drainage system is a complex intervention in the building structure. Mistakes can lead to severe water damage.
1
Conduct an infiltration test
Before construction begins, it must be checked whether the soil can absorb the water. This determines whether the water is allowed to infiltrate on the property or must be drained away.
2
Obtain permits
Check with the municipality whether a water protection permit is necessary. A connection to the sewage system always requires official approval.
3
Excavate the trench
The trench is excavated down to the base of the foundation. Caution: Working on foundations involves structural risks and requires professional safety measures.
4
Lay pipes and fittings
The pipes are laid with a gradient of 0.5 to 1%. For changes in direction (e.g., at house corners), two 45° bends are preferable to one 90° angle so as not to slow down the water flow.
5
Integrate flushing ports
Install flushing ports at strategic points. These are absolutely necessary to be able to maintain and clean the pipe later.
6
Backfill with drainage gravel
The laid pipes are encased in drainage gravel and often protected with a filter fleece so that no mud clogs the holes.
Always contact a certified civil engineering company in the event of moisture damage or complex hillside locations.
Frequently asked questions about drainage pipes
Here you will find the most important answers regarding costs, maintenance, and regulations for drainage systems.
A precisely calculated, slight gradient ensures that the water drains away reliably without dirt or mud accumulating in the pipes.
For a professional high-pressure flush by a pipe cleaning service in Switzerland, you should expect costs starting from approx. 300 to 500 CHF, depending on the pipe length and the degree of soiling.
Over time, mud, limescale, and fine roots settle in the pores of the pipes. A professional flush restores permeability and prevents backwater, which can lead to expensive moisture damage to the foundation.
Generally, no. Seepage water is considered unpolluted extraneous water and must infiltrate on your own property. Exceptions are only granted if no other technical solution is possible.
Durability is largely determined by professional installation, the choice of robust materials such as vitrified clay or special plastic, and consistent maintenance. Well-maintained systems operate trouble-free for many decades.
If you notice damp walls in the basement, do not hesitate to contact an expert for a sewer inspection.
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