Septic Soakaway

[lumsdale]

We are moving to a house which is not connected to the main sewer system. It has a septic soakaway which drains away toward the back of the house. How does this system work and how is it maintained?

[buildersmate]

It consists of two (or more) pits, typically in concrete if old, into which the sewage flows sequentially. Solids separate and fall to the bottom, liquids flow into the soakaways that are typically arranged in a fan shape to enable the liquids to dissipate into the ground. Partial composition of the material occurs in the pits. Every year or so you have to have a tanker call to pump out the solids in the pit. There are no moving parts and no other maintenance costs.
Modern digesters are more sophisticated, but there must be tens of thousand of these types of systems in use in rural areas of the UK.

[Clanad]

As an aside... except for some differences in terminology, I easily recognize the similarities to our systems here in the U.S. We live in a rural area of the west and almost everyone is on such a system. Our's consists of the buried tank, which is concrete and holds about 1,500 gallons. We usually only have one tank, which drains into what we call a 'leach field'. This is built of perforated PVC pipe 4 inches in diameter and arranged in several rows at least 25 feet apart. They are at a depth of about 5 feet, mainly due to our frost level caused by severe winter temps of at least -25F or more. The actual trenches in which the pipes lay are about 6 or 7 feet deep with the bottom half filled with coarse gravel. Once the PVC is layed (with the appropriate 1/4 inch per yard drop for drainage) another layer of at least 2 feet of coarse gravel is added and then backfilled with dirt. Many systems are 30 or 40 years old, with no problems,
One word... we only have ours pumped to remove the built up sludge every two years. The County Extension agents have shown that to pump more often destroys the bacteria needed to breakdown the solids. The bacteria are essential to cleaning the discharged liquid. In fact a neighbor admitted that she had never had hers pumped for more than twenty years until some required minor maintenance last year. The pumper said there wasn't really anything wrong with her system (but pumped it anyway and charged her). Our soil is fairly sandy so the evaporation and 'leaching' works quite well...

[Silvercat]

At our last house we did not empty the septic tank for over 10 years and only did it then because we were selling it.

In all that time, we had no problems with it at all.

[kwicky]

As silvercat has said you can go for many years before the solids need removing but what happens is that when that chamber fills it will overflow into the 2nd chamber where the liquids are. The liquids are designed to filter out into the surrounding earth but what happened to ours during heavy rain was they overflowed onto the surface which caused an almighty stink.

If you visit the countryside you will find many properties using streams to take away the excess effluent. It should be banned as a health hazard!

[wastetech]

It is OK to flush ordinary toilet paper down the loo but NOT wet wipes, tampons, make-up remover pads, panty liners, cotton buds, Cig butts, etc. as these don't degrade quickly enough and will fill the septic tank.

UK Building REgulations state that the septic tank should be emptied every year as UK models are sized to hold only one years sludge build up. Media URL: http://www.wte-ltd.co.uk/septic_tank_products_information.html
Description: Septic Tank Systems explained and problems resolved