Information on Sewers



This is the area of home maintenance that best fits the mantra:

If it ain’t broke don’t fix it!

Get it looked at when you buy the house then forget it, completely, until the unhappy day that you get that first unmistakable whiff.

What is a Sewer?

It is the pipe which carries waste water away from your house. This includes water from sinks and washing machines. This can be referred to as grey water. The other type comes from the water that is used to flush toilets, including the solid matter it contains. This is called black water.
Rainwater will also collect into the sewer via your guttering.
Sometimes there will be a two separate sewers, one for the rainwater (
the storm sewer) which usually heads off towards the nearest river and one for the domestic waste water (the foul sewer). In older properties it is likely that there will only be one pipe for all of the water and this is known as a combined system.
The water leaves the house and makes its way, with the help of gravity, into the street where it joins up to the main sewer along with those of your neighbours. It is then transported away to the water treatment plant.
There are exceptions to this, which I will come to later.

Shared Sewers
If you live in a detached house, it could be expected that your sewer will only pass beneath your land on its way to the main sewer in the street and that you will be responsible for its maintenance. If you live in an attached property, it is likely that your sewer will connect with that of a neighbour’s and may also pass beneath his land before it joins up with his and then on to the main sewer. If this is the case and there are maintenance issues, you will need to determine who is responsible for what and it will be time to dig out all that ‘bumph’ the solicitor provided you with (at great expense!) when you bought the property.

Manholes and Inspection Chambers

Connections require an inspection chamber or a larger manhole. This is a vertical access shaft which connects the surface to the sewer and it permits cleaning and repairs to be performed. They are at every point where two or more pipes join or when a significant bend is required.
There should also be a chamber where the pipe leaves the property to go into the road. This should incorporate an “interceptor” which is usually a slight “U” bend which acts as a sump. This eventually collects stuff which you drop down the toilet by mistake, so you can put your hand down and fish it out.
This act is probably the vilest thing any normal human being will ever be required to do, ever, in the whole of their lives. I suggest that if your wife’s engagement ring is down there and it’s worth more than £10,000, do it! Anything less, get in an ‘expert’ or forget it!

Older inspection chambers are usually made from 
rendered brick, or exposed engineering bricks. Modern chambers can be constructed from brick, deep concrete rings or rectangles or polypropylene.

A complete Inspection Chamber (base, riser and cover) in polypropylene costs from around £80.

Manhole covers

This is an item which you may actually need to replace and fit sometime, particularly if you drive your car over it on a regular basis.

A manhole cover is a flat plug designed to stop you from falling into the chamber beneath it. Furthermore, the older ones are made of cast iron or steel and have been known to ‘disappear’ due to the value of the metal, or their design. If you want to buy a matching replacement, the older it is, the less chance there will be of finding one unless you are prepared to pay through the nose for it! Stainless steel covers are available as an alternative.

Covers are now made of less exciting material such as pre-cast concrete, glass reinforced plastic, composite resin or galvanized metal. Not all of these will withstand the weight of a car though.

Prices range from £20 upwards, with a composite resin one costing around £50 and an iron one upwards of £120.
There are plenty of styles available to suit your purpose. For example, you can get one that looks like block paving, which would be handy to ‘match’ your patio or driveway.


Blockages
So, why do your sewers block up? Usually it’s too much toilet paper, feminine hygiene items or liquid fat which goes down the plug hole, solidifies very quickly, then builds up and stops the flow.

So who cleans it all out? Well if you’re brave
you can. Borrow some rods and plug away for a while. It usually does the job. There are fewer more satisfying sights than watching a full manhole suddenly emptying out. One minute you are nearly gagging, pushing away with three metres of black pipe covered in unmentionable vileness. The next minute, a hideous brown whirlpool appears before your very eyes and thirty seconds later it’s all gone!

If you get a bloke in, he will come with water jets and suggest sending a camera down there, then charge you accordingly. You will probably be so desperate by the time he gets to you that money will become no object. Best case scenario is that you’ll get small change from £100.

There’s other stuff as well that causes blockages such as ground movement (pretty serious this), plants getting into manholes or bits of the manhole itself falling into the channel.


Not on Mains Drainage?

Well, the process is just the same but instead of disappearing under the road, the pipework ends up in either your cesspit or your septic tank. One for each house usually. Try not to share!

A cesspit effectively only stores the sewage for a while. It then has to be pumped out and taken away, regularly.

A septic tank is more complicated. Here the 
solids sink to the bottom where bacteria digest them. The residue eventually has to be pumped out, but usually only annually. The water leaves the tank continuously, to disperse via perforated pipes into the soil where it drains slowly away. Hint: Plant your tomatoes here.