Relief Point

A so-called relief valve prevents sewage from simply flowing into the house when there are problems with the sewer system. However, many homes do not have a relief valve.

According to the Building Code (which sets forth the structural regulations for all buildings in the Netherlands), businesses and residents are required to have or install a relief point on their own property. If there are problems with the sewer system, this relief point ensures that sewage does not flow directly into the home. In practice, very few homes have such a relief point.

Cesspools

In the past, houses had what were called “septic pits.” These were brick-lined pits in the yard where the pipes converged. These pits were prone to clogs, but they also had an advantage: if something went wrong, it happened in the pit and not inside the house. Often, the septic pit also served as a vent for the sewer line.

No More Wells

Nowadays, homes are connected to the sewer system via PVC pipes. There are no manholes in between. If there’s a clog, the wastewater takes the easiest route. That often means sewage backing up into the house.

In the Netherlands, more and more separate sewer systems are being installed: wastewater (such as from toilets and showers) is discharged separately from clean water (such as rainwater from the roof). Because rainwater flows through a different pipe, the wastewater pipe is no longer connected to the gutter. As a result, it receives less aeration.

Aeration is important

If a pipe isn’t vented at all, or isn’t vented sufficiently, it can cause problems. You’ll often notice this when a P-trap (the curved pipe under the drain) gets sucked dry. When that happens, the odor trap no longer works, causing you to smell sewer odors in your home. You can fix this yourself or have it fixed. You can read more aboutthis onthe “Smelly Drain” page.