Does anyone know anything about septic tank land drains?

[endymion]

Our septic tank is circa 1958 . Brick built, two chamber. Don't know where the land drains are really.

We had some trouble with a blocked drain ( inlet about four years ago. Rodded it and it worked again. This was the first time OH had ever seen a septic tank. he isn't much wiser now. he thinks I should be the fount of all knowledge but I know even less.

We had a blockage in the drain and I know it came out over the inspection cover and its gone on for sometime because I didn't tell him. I thought since the problem was the same as previously, the cause was the same ( blocked drain - or partly blocked since the water did run away over time)

He rodded it the beginning of this week.

The drain is now clear.

However, OH is telling me that he thinks we have a blockage on the outlet pipe ( land drains).

We pumped out the tank and he now has a more or less empty tank to look at. Water is going in but he says its not going away properly. He thinks its land drains problems and the water cant get out on the outlet side.

Its a bit difficult since we cant really see the outlet side too well as its over on the far corner of the tank and we don't seem to have a second inspection hatch. It looks as if it was capped somehow.

So, how can you tell if there is a problem with the land drains?

How can he fix it?

Thanks.

[Peter Crosland]

In theory the sewage drains into the first chamber and the solids settle to the bottom. A crust forms on the top and natural bacteria digest some of the solids. The remaining solids have to be pumped out annually or sometimes more frequently. The liquid flows over into the second chamber and an outlet from this runs into a series of pipes (land drains) set in gravel. The fluid soaks away into the surrounding soil. With a tank of this age the gravel beds are probably totally clogged with debris and no longer functions properly. Fixing it is not a DIY job unless you have experience. You need to find a properly qualified contractor who can advise what is needed. It will almost certainly mean that the Environment Agency will get involved, and they will have to give approval to the works followed by building regulations approval. If the EA are not prepared to give approval then you will have to consider connection to mains sewage if it is available, or a subterranean treatment plant. Remember that if the EA finds out your system is causing pollution they can prohibit further use or even prosecute.

Peter Crosland

[endymion]

Thank you for the information and I will pass this on to him.However, until we pumped this tank last week it had not been pumped as far as I know in the last fifteen years. That was when we moved in. I cant say before that.

My mother has a tank which is like ours and hers had done firty odd years unpumped . Like ours the inlet has on occasion had to be rodded but nothing else. There are those locally who say the septics dont need emptying at all .

The land drains on none of these have ever gone wrong and I was told this morning of one tank which has land drains which were laid sometime back in the 1900's and are still going. I am not convinced that our land drains have packed up but OH is.

How can we tell ?

I am not saying anyone is right or wrong. I am asking because the information I get is so conflicting.

[endymion]

I have to add I am reluctant here to get someone in for a number of reasons.

Firstly when our house and septic were put in they were probably quite legal but the rules seem to have changed and we propably wouldnt get permission now.

Secondly the contractors seem to be out to make a fast buck and wont tell us the whys and where fores and that always bothers me. Asking them to put in new land drains is a big job and they are jumping at it for no reason than money.

Thirdly I simply do not know if anything is wrong. My OH says but he knows no more than I do. To be honest it looks OK to me now and I am inclined to wait and see.

The land drains were working fine last year as evidenced by the growth of grass over the area one side of the garden as opposed to the other. I still think if the land drains are sluggish it might be that we have had

10 months of non stop rain here , high rivers and water tables and an almost permanent flood alert, followed by snow and - 5 tempretures. We are well above the water table but not necessarily immune form water logged ground and frozen soil.

I am just worried that we could just make things worse.

>

[Phil L]

You can't make it worse - they either work or they don't, and if they are taking the water away, they are working as they should. If there is a problem in the future WRT the water backing up, you can dig around the outlet and trace it's direction (this may or may not require a lot of digging) to it's final destination, here you may need to dig a soakaway, or if the drain has collapsed before it reaches the soakaway, you may just need to repalce a small section.

If you pay someone to do it, this is what they will do but as for giving you a price beforehand - how can they? - they don't know wheher the run is five metres long or a hundred metres long, so their price will be a 'worst case scenario' kind of thing

[Rob G]

As a similarly equipped septic tank owner - ie relatively large brick chambers - I will add what my experience and knowledge is.

Firstly, these old brick tanks, mine is 1920's - are sufficiently large that they can tolerate all sorts of abuse that the modern fibreglass bottle tanks won't. That is they do not have to be pumped out yearly - they are quite happy to last 10, 15 years or more. They are also more tolerant of some of the more aggressive chemicals that are put down toilets and the likes.

I have had to clear my inlet a couple of times - famously on the day of my second child's baptism party; a nappy liner. Then some years ago the outlet blocked. Don't tell the EA but round here all the tanks discharge into a small burn - mine by a vertical 2m pipe to a buried 18" culvert. In my case the pottery land drain from the tank outlet to the drop had filled up with soil - after 60 years that wasn't that surprising with that type of drain pipe and apart from the unpleasant mud was easy enough to resolve with modern pipe and pipe laying techniques.

You should be able to locate this outlet pipe easily as it will be near the top of the second tank and not that deeply set.

Rob

[The Natural Philosopher]

Fill the second chamber and see if its draining away.

Dig out the outflow and (in my case) remove hibernating frog in mud nest from it ;0-)

Its not rocket science, its cold, dirty and tiring..

[The Natural Philosopher]

One good test..and it helped me - is to ram a hose down the outflow drain and see how far it gets.

It may also back flush any minor blockages, and it will tell you roughly how far away the blockage, or pipe end, is.

If you can then work out the direction..

[Peter Crosland]

You need to remember that the correct functioning of a septic tank depends on a number of factors, and before drawing conclusions make sure that you are comparing like with like. For example the size of the tank relative to the number of people using it, the soil conditions and the quality of construction are major factors. Having lived in four houses connected to brick built septic tanks that were built between 1900 and 1950 I have to say that the two that gave trouble were those that had not been emptied regularly. The problem being that if the output from the second chamber contains any solids it will inevitably result in the soakaway and land drains becomeing clogged. Unless you do proper tests including digging some test holes in the soakaway area it is hard to tell what condition it is in. As I said before you need to get someone qualified to examine it before you can make an informed decision what to do. Make some enquiries about companies that do the sort of work and ask for references. Get several professional opinions.

Peter Crosland

[Roger]

The message from "endymion" contains these words:

Off course water isn't flowing out of the tank at the moment.. Water shouldn't flow out of the septic tank until it reaches the outlet pipe which is going to be somewhere close to the top. You will now have to wait for the level to stop rising before you can see whether or not you have a land drain problem but if I recall correctly what you said earlier it seems to me that you have a problem with the pipe going into the septic tank as evidenced by flooding from an inspection cover further up the line.

[Roger]

The message from "endymion" contains these words:

The proof of the pudding is in the eating and there are thousands of septic tanks around the country that have been going decades without being emptied. I don't know how true it is that some require emptying in under a year but if they do then they are more cess pit than septic tank. This notion that septic tanks need to be emptied frequently seems to have come in with the introduction of single tank systems but may have something to do with unthinking users flushing powerful chemicals into the tank and destroying the bacteria that likes to make a meal of the waste. Theory used to have it that a working septic tank has a firm crust on the surface in which there are aerobic bacteria feeding on the floating waste and at the bottom of the tank anaerobic bacteria feeding on the sludge at the bottom. Such activity needs to be started and the country remedy used to be a rotting carcase of a rabbit or some other easily obtained dead pest.

I know of at least 3 septic tanks that have been going for over 40 years without being emptied but I don't know of a single one that has needed emptying in under a year.

A neighbour (who does have his tank emptied every few years) had a land drain problem last year and had to get a man with a excavator in. Turned out that the outlet pipe was completely blocked with tree roots.

Simple. If the septic tank cover floats off into the sunset you have a land drain problem. If the level within the tank doesn't come close to the cover you haven't a land drain problem.

[Steve Firth]

I agree. We have two septic tanks, one Kargester onion and another with a "three chamber + anaerobic filter" design. Neither have ever needed emptying. After running the Klargester for 18 years I decided that maybe I should have it emptied. That was the worst mistake I've made in a long time. The septic tank stank for months until the bacteria re-established themselves.

The bloke emptying the tank said it was pointless (after he had taken the cheque, of course) since there was very little sludge in the tank.

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "Peter Crosland" saying something like:

Not so. Every septic tank I've been involved with has happily worked for much longer than that.

[The Natural Philosopher]

:-)

I rented a house once with 5 other students. One guy was the ONLY person to use the downstairs loo. He neglected to tell us it was filling up.

Alerted by the smell, we looked, saw and proceeded to lift a manhole outside..and rapidly drop it back and call the landlord.

[Pete Verdon]

Yep. My parents have a photo from their first house of kick-starting the septic tank with a dead rat. My father having the sense of humour he does, they dressed it up as a mock military funeral, with bugler playing on a length of hose and funnel, and dad dropping the rat from a hand rigidly extended at shoulder height while standing to attention in his welly boots.

Pete

[Jonathan]

Septic tanks should not need emptying. One thing you can do is get some dye and put it in the tank and see if it appears anywhere, which should indicate where the land drains go. On a house that age, they will most likely be clay pipes and may have collapsed under pressure. We had this problem and a local agricultural contractor fixed the problem with a digger at very little cost (was 20 years ago).

Jonathan

[The Natural Philosopher]

They do.

There is an inevitable build up of insoluble material in them.

it may take many years, but eventually this gets into the outflow, and blocks it, and in the meantime it will reduce the capacities of the settling tanks.

Howevr teh cost of e.g. digging out the outflow and redoing it every

15-20 year versus emptying it every 5, are probably not too different.

One thing you can do is get

Diggers are best. Once you know here the pies are, get in there with a mini digger, and make good that soakaway.

One thing I did notice on going from a septic tank to an aerobic tank, was that the garden soil downstream off the outflow, no longer smelt of bad breath and streptococcus. Neither did the area around the outflow.. What comes out of a septic tank is buy no means clean really..which is why they are deprecated if not outright banned for new installations.

The Klargester only smells when the motor stops. As it is right now..bugger. They were supposed to be getting back to me..