What is a strijkriool?
A strijkriool (Dutch) is a sewer that runs parallel to the main sewer but at a shallower depth and with a smaller diameter. It is laid where the main sewer is too deep for house connections to join it directly. There is no fixed English equivalent; in effect it is a shallow collector sewer running alongside the main one. The name comes from the Dutch verb strijken, to pass along: the pipe runs alongside and above the main sewer.
In the Netherlands a house connection is normally laid at a depth of about 1 metre at most, while a main sewer can lie as deep as about 3 metres. The strijkriool bridges that difference. Houses connect to it, and it drains by gravity into the main sewer further along the network. It is mostly found in rural areas, where it often connects through a pump well and a rising main.
Dutch municipal guidance also describes it as the public gravity pipe carrying foul water, without rainwater, between a pump or buffer well and the private part of the house connection. It may lie in private ground but is still maintained by the municipality.
In practice
- Ask the municipality where to connect. If you build in the Netherlands and a strijkriool runs past the plot, you connect to it, not to the deep main sewer.
- Know where your responsibility starts. It begins where your house connection meets the strijkriool.
- Keep the route clear. If the pipe crosses your garden, do not build over it or plant deep-rooted trees on it; the municipality needs access.
- Keep rainwater out. A foul-only pipe ending in a pump well can be overloaded in heavy rain.
Common mistake: treating the strijkriool as a private drain. It is a public sewer, even where it lies in private ground.
Related terms
- Sewer
- Pumping station
- Sewer rehabilitation
- Alternating sewer system
- Drainage
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