Sewerage, Drainage, Sewers and Laterals FAQs
Q:Who has the responsibility of maintaining the drains?
A: Where a property has a dedicated connection to the mains drainage system the householder is responsible for maintaining that system up to the point that it joins the main sewer.
The local council was responsible for cleaning elements of a communal system provided that the system was constructed before 1937, but they were also empowered to reclaim the cost of repairs from the householders benefiting from the works. For systems connected after 1937 the householders are responsible for maintaining the systems and they must collectively share the costs of maintaining and cleansing the sewer.
The situation is now more complex, because since the privatisation of the water companies within the UK some councils have had their sewers adopted by the water companies. Others have transferred their sewers to the local Housing Associations.
There are currently discussions about whether the water and sewerage water companies will take over the responsibility for maintaining some private drainage up to the first manhole or inspection chamber on the private system. This has yet to be agreed, but could happen by 2010.Q: What sorts of drainage system are there?
A: The most commonly used system in the UK is a single stack system whereby the wastewater and soil pipes are all connected to the same stack. This is also known as a primary ventilated system.
There is also a secondary ventilated system, which used to be known as the ventilated stack system, whereby a ventilating pipe is installed in addition to the stack which improves the flow capacity of the main stack. This alleviates pressure fluctuations within the system by allowing the movement of air within the pipe work.
In older houses the waste pipes are often divided into two separate pipe systems.
Waste from the WC is fed directly into a pipe of a large diameter - the soil stack, leading to the underground drains. Gases from the drain are discharged into the open air above the height of adjacent window openings to safely ventilate the sewer. The waste pipes from baths and washbasins reach a waste stack via a hopper funneling the water into another vertical pipe.
Q: Where do my pipes go?
A: Whilst the drains run underground and therefore cannot be seen, they nearly always run in straight lines between inspection chambers, gullies, fittings and stacks. Inspection chambers or manholes should exist at every point where pipes meet and where the direction or gradient of the drain changes.
Q: What do the manholes and inspection chambers look like?
A: In older properties the inspection chambers can be brick built rectangular structures with cast iron or galvanised steel covers. In newer houses plastic chambers can often be found which are usually circular with iron or steel covers.
Q: How do I know whether I have a blockage?
A: An unpleasant smell from the inspection chamber is usually the first sign of a blocked drain. Sometimes if the blockage is severe, sewage can overflow from a gully or from under the cover of an inspection chamber.
Q: How do I lift a manhole cover?
A: Firstly, be careful, use thick gloves and protective clothing such as overalls and some stout footwear with toe protection. Whilst many covers are light-weight cast iron covers are generally very heavy!
If the cover is rusted in around the frame or the gap between cover and frame filled with soil, use a screwdriver to scrape around the edge, then tap round the edge with a hammer.
If it is still resisting movement, tap the cover gently with some wood. The vibration should be sufficient to release the cover from its seating. Insert a spade under one edge to raise the cover, place some wood under the edge to support the weight and lift it aside.
Manhole lifting keys will help raising the lid. A strong hook may help if the covers have small handles in the form of small bars across the indents; or attach loops of string or wire through the bars to a large piece of timber which can then be lifted by two people using the timber as a handle.
If the cover is secured by screw bolts or screws soaking them in oil before attempting to undo the fastenings will help.
Q: How do I find the blockage?
A: Lift the manhole cover nearest the house. If the manhole is clear, the blockage is probably between the manhole and the house. The most effective tool is a set of drain rods, because they are flexible. Sometimes a small blockage can be cleared by plunging with a mop or a stick. When the outlets and inlets are hidden by effluent flexible rods are usually required.
Screw two rods together and slide them into the chamber in the direction of the suspected blockage. Screw on another rod and continue pushing, whilst manoeuvring the rods vigorously back and forth. Always turn the rods in a clockwise direction as you push them, this will stop the rod loosening or a joint undoing whilst underground. Continue until you feel the blockage clear.
The chamber should then be flushed thoroughly to remove all traces of debris. Sometimes the blockage is caused by a build up of fat in the chamber. Flush hot soapy water through the chamber to help remove any remaining debris.
If the blockage cannot be located, it must be further down the run of the sewer. Lift the next manhole cover in the line and repeat the above process.
If the lowest manhole is blocked, then the blockage must be between that manhole and the sewer. If it is an interceptor trap, the blockages are nearly always within the trap.
The trap is usually full of effluent, some stoppers are on a chain otherwise feel for the handle with a stick and try to hook it out of its socket. Try not to let the stopper fall and block the trap. Use the rods through to the sewer and then flush out the channel with running water to clear debris.
Replace the stopper and before replacing the cover smear a little grease around the frame to stop any rust in the future.
