The chamber is the point through which the pipe is inspected, flushed and cleaned without digging. We install plastic inspection chambers and concrete-ring manholes, both in new systems and in existing networks, in Riga and the Riga region.
Where a sewer chamber is mandatory
Building code LBN 223-15 “Sewerage Structures” states that manholes are installed:
- at junctions, where another pipe joins;
- where the pipeline changes direction, gradient or internal diameter;
- on straight runs: every 35 m for pipes with an internal diameter of up to 200 mm, less often for larger pipes.
At a private house, this usually means a chamber at or near the house outlet, at every bend, where a sauna or a second building joins, and before a septic tank, biological treatment plant or pump station. If the house is connected to the city network, in Riga that network ends at the control chamber 1.5–2 m from the street's red line (the street boundary); the section from the house to it is the owner's responsibility.
Sources, checked on 30 October 2026: Cabinet Regulation No. 327 of 30.06.2015 “Regulations on Latvian Construction Standard LBN 223-15 “Sewerage Structures”” (points 73, 74, 78, 79; version of 09.09.2020); Riga City Council Binding Regulations No. 17 (point 3.6). LBN 223-15 does not apply to the internal sewerage of buildings.
Plastic inspection chamber or concrete-ring manhole
| Plastic inspection chamber | Concrete-ring manhole | |
|---|---|---|
| Working in the chamber | No one climbs in; the pipe is cleaned and inspected from the surface | You can climb down; needed if work has to be done inside |
| Best for | Private house connections, shallow and medium depths | Deep networks, large pipes, junctions of several lines |
| Connections | Factory-made stub pipes with rubber seals | Holes in the rings that have to be sealed |
| Installation | Quick, no crane needed | Machinery needed to lift the rings |
| Groundwater | Light, so it has to be secured against floating up | Heavy, but the joints can let in water and sand |
LBN 223-15 sets the manhole diameter for networks according to the pipe: for pipes up to 600 mm it is 1000 mm, and the part where a person has to climb in must not be narrower than 700 mm. Inspection chambers under 1000 mm in diameter, which no one enters, are allowed in water utility networks after approval by the operator. On private property, plastic inspection chambers are the usual solution.
Cover, load and height
The cover is chosen according to what will walk or drive over it. On a lawn or a path, a light cover is enough. In a driveway, you need a cover designed for cars (under LVS EN 124 usually at least class B125, but C250 or higher where traffic is regular or heavier). You also need a top section that transfers the load to the ground rather than to the chamber pipe.
A telescopic top section lets you set the cover exactly level with the ground or paving and adjust its tilt. The cover must not end up under a layer of soil: a chamber nobody can find will not help when the pipe clogs.
How we install a sewer inspection chamber
- Location and levels We set the levels and fall of the inlet and outlet pipes so that water does not stand in the chamber.
- Digging and base We dig the pit and prepare a compacted sand or gravel base; in high groundwater, a concrete base and anchoring against flotation.
- Chamber and connections We set the chamber in place, connect the pipes with seals and level it.
- Backfilling in layers We backfill with sand in layers and compact each one. This decides whether the chamber will be tilted or crushed a year later.
- Top section and test We fit the top section and cover, test the flow with water and restore the surface.
A chamber in an existing sewer
A chamber is often added later, when the pipe keeps clogging and there is nowhere to clean it, or when an old concrete manhole has collapsed. In an existing network, we dig out the pipe, cut out a section and insert the chamber with adapters to the material and diameter of the existing pipes.
If blockages keep recurring in the same place, we also check the cause: sediment in a pipe with too little fall, roots in old joints or grease from the kitchen. If water stands in the chamber all the time, it needs to be pumped out (see septic tank pumping).
How much does it cost?
Sewer installation costs from €25/m. The price of a chamber depends on its diameter, depth, material and cover class, so we include it in the estimate after a site visit. The price is also affected by groundwater (base and anchoring), restoring paving or asphalt, and whether the chamber is built into an existing network.