What is an inspection chamber
An inspection chamber, in Dutch an ontstoppingsput, is a vertical pipe, usually PVC, that rises from the sewer pipe to ground level and is closed with a cover. At the bottom is a fitting with an opening into the pipe. Through this chamber an engineer can enter the pipe in both directions with a spring cable, high pressure hose or inspection camera: towards the home and towards the main sewer. Nothing needs to be broken open and no dirty water comes into the house.
Inspection chambers are usually in the front garden, the pavement or the driveway, often close to the property boundary. The cover is sometimes round and small and may have disappeared under gravel, tiles or plants. A home with a separate system sometimes has two: one for foul water and one for rainwater. Keep the cover clear and accessible, so an engineer can get to it straight away in an emergency.
Boundary chamber: the line between owner and municipality
A boundary chamber is an inspection chamber placed exactly on or near the property boundary that marks the transition between the private drainage and the municipal house connection. In many municipalities everything on the house side of the chamber belongs to the owner, and everything on the street side to the municipality.
That also makes the chamber handy with a blockage. If the chamber is full of water, the blockage is usually downstream, in the section towards the street. If the chamber is empty while the water in the house will not drain away, the blockage is in your own pipe. The rules differ per municipality, so check with your municipality if in doubt before having work done on the street side.
What is an access fitting
An access fitting is not a chamber but a fitting in the pipe itself. It is a short piece of pipe with a screw-off or removable cover, fitted at strategic points in the internal drainage. You often find it at the bottom of the soil stack, in the crawl space at the transition to the underground drain, or just inside the outside wall.
An access fitting gives access to a pipe that would otherwise only be reachable via a toilet or trap. That saves a lot of time and means nobody has to work through the toilet pan. Make sure the cover stays accessible and is not built in or sealed shut. Only open the cover yourself if the pipe is not full of water, otherwise the contents will flow out as soon as you unscrew it.
How to find the inspection chamber
If you do not know whether your home has an inspection chamber, there are a few places to look. Look for a small round or square cover made of plastic or cast iron, sometimes with lettering. The cover usually sits level with the paving or ground and after years is often overgrown or hidden under a layer of sand or gravel. Look for example:
- in the front garden or on the driveway, in line with the point where the drain leaves the outside wall;
- just behind the property boundary, where the garden or driveway meets the pavement;
- next to the front door or below the meter cupboard, where the pipe often leaves the home;
- in the back garden for homes whose sewer runs to a rear path;
- on building drawings, in the purchase documents or in an earlier survey report.
If you find nothing, an engineer can follow the pipe with a camera fitted with a transmitter and point out exactly where the chamber is or should be. With a receiver above ground the position and depth of the camera head can be determined. Mark the spot afterwards, for example with a tile in a different colour, so you find it again straight away next time.
No inspection chamber: what now
Especially in older homes an inspection chamber is sometimes missing. The pipe can then only be reached via an access fitting inside or via the toilet. That works, but is less convenient, particularly with long external pipes or a blockage close to the main sewer. An engineer then has to bridge a longer section with the spring cable or high pressure hose, and it takes more work to establish which side of the property boundary the blockage is on.
Some municipalities install a boundary chamber during sewer works in the street, or do so on request. A chamber can also be added during a repair of the external drainage. Check with your municipality about the options on the street side. On your own property an access fitting or chamber can often be added when the pipe is exposed anyway, for example during a garden makeover or when a new driveway is laid.
How Bosmans uses the inspection chamber
For the engineers of Bosmans Rioolservice the inspection chamber is often the first point of contact. Through the chamber they quickly establish which side the blockage is on, clear the pipe with spring cable or high pressure equipment and map the route with the inspection camera. If the pipe turns out to be damaged, you receive advice on repair or relining. You hear a firm arrival time and the rate in advance.