This a long shot, and one which may result in a lot of eloquent effluent based banter, but are there any septic tank experts amongst the STW collective?

We live in an old farmhouse which has a tank which empties out into a burn at the bottom of the garden.  All waste water from the house goes into the tank and clear water comes out of the tank into the burn.

The mud around the tank outflow is black,  different to the brown mud along the rest of the burn but doesn’t smell bad. In fact the whole system is pong free apart from when there has been a spike in No. 2 toilet activity.

There are 4 of us in the house (2 adults and 2 young kids ) and we have lived here for 2 years and not emptied the tank.

Should we get the tank emptied? Advice on line is mixed. One school of thought is to leave well alone as emptying it, or removing some of the contents, may have a negative impact on the natural decomposition process in the tank. Others recommend getting the tank emptied on a regular basis.

There’s quite a drop in elevation between the outflow pipe, the tank and the house so the liklihood of the system backing up is very unlikely, unless of course the outflow got blocked.

So, leave well alone or get the tank emptied in part or completely?

You do know what is in there, don’t you? 🙄

Maybe yours is already backing up, you just don’t know it yet…

FWIW Ours is emptied every two years. Not sure about elsewhere, but in Scotland our local water company contact us and then we pay once they’ve been.

We’ve recently moved into a house with a septic tank. The previous owners didn’t touch it for 5 years or so, it was only when someone said it should be emptied that did so every 18-24 months.

My FiL said from his experience it should look after itself.

We’re not sure which way we’ll go yet…

You’re supposed to “desludge” it every so often. Two years sounds like you’re touching cloth at the moment – I’d get it emptied.

We have an industrial “septic tank” – you need to get the sludge out every 2 years or so for them to work properly. It reeks.

Too full and channels form through the mass and stuff pretty much goes straight out, or your support media collapses and the EPA give you a kicking.

Septic tanks are real simple. It’s a place for shit to rot.

Once it’s broken down adequately, the liquid supernatant rises to the top and is discharged either to ground via soak away or into the nearest burn, which is less preferred because it’s still nutrient rich and deoxygenates the water. Chances are the reason the soil is black is because the localised area around the discharge is anoxic which changes it’s redox potential and results in reduced iron from sewage, instead of the orange of exidised iron.

The remaining solids settle as sludge in the bottom and slowly build up.

If you can see sludge or other solid matter beyond the odd floater at the top, you need to get it emptied.

Periodic emptying should be done as general maintenance, but how how often depends on, uh, how much matter you put into it!

Crap topic for a Sunday night floating to top of threads shocker.

Without putting to fine a point on it – if it needs emptied – you’ll know about it (although it migh just be something as simple a slow draining toilets etc. We rang our local emptying comapany not long after we moved into the house and the guy was worryingly familiar with out tank. He emptied it once, and we’ve since had him back to look at what turned out to be an unrlated blockage between the house and the tank. I’m guessing ours will need attention every 2-3 years, but it does for whatever reason take all of our rainwater, which means it’s always going to struggle in this sort of weather.

Anecdotably – you can recolonise the bacteria using live natural yoghurt? I’ve never found any on offer so I haven’t spoon fed our toilet.

We had one in one of the houses I lived in as a kid.

It absolutely stank when it needed emptying and was ok when it didn’t.

Emptying the bath used to push it over the edge iirc.

I used to empty mine about every year or so. It was a pretty ‘crappy’ old one though.
Anyway, this thread reminded me of a funny story. I was chatting to a farmer/customer at the time (maybe 1995 ish) about the price of septic tank emptying by a local company & he said he could do it for a drink down the pub, which I obviously went for (being a bit skint at the time), so he came with his tractor & shit sucker/spreader & did it. A couple of days later he called in & told me what had happened when he’d gone to empty the ‘sucky/spready’ tank. He’d been emptying the tank & the flow had stopped so he went to the nozzle to check what was wrong & noticed something jammed in the outflow nozzle, (which happened to be a small plastic plantpot from my septic tank, which I can explain if required) went to the tractor cab & grabbed an iron bar, went back & whacked the nozzle.
Except he forgot to disengage the PTO to the pump first. Resulting in him being showered in (a lot of my) shit.

True story!

Ours is done annually, 5 of us plus regular visitors. Not a particularly big tank and when we first lived there it used to overflow and stink quite regularly but diverting grey water from sinks, washing machine etc from it into a separate soakaway made a big difference, works fine now and apparently it’s better to not have detergent residue going in them as it hinders the natural bacterial breakdown or something.

My architect dad always used to say that if a septic tank is working properly it should rarely need emptying. We replaced ours about 11 years ago and put in a new soakaway – it’s never been emptied and doesn’t smell at all.
I am not an expert though.

Cheers all.

sharkbait – how many of you are in your house?

We just moved into a house where the previous owner installed a new septic tank system a few months before. The blurb he left from the manufacturer recommended annual/18month emptying. It depends on tank size and volume of material going in.

Also recommended emptying about 90% of the tank, leaving some of the good stuff in the bottom to ensure it keeps working.

Go easy with the bleach when cleaning toilets and obviously nothing goes down the pan that won’t break down (avoid flushable baby wipes as they clog up the system).

Ours is emptied yearly. 3 houses connected, about 9 people’s sludge. Usually get charged for 4 or 5 cubic metres.

It needs replacing soon as it’s built to an old standard which will be illegal round here by 2020. Going to cost about 12 grand. 🙁

A neighbour had a two tank system, which he didn’t know was a two tank system (his deeds were incredibly vague and no plans provided when he moved in), so he’d only been emptying the bottom tank. For 10 or 12 years. When they found the top tank (under a wooden deck) it was basically solid, took em 2 days and special equipment to break it all up and empty it. 5 cubic metres of solidified shit. Cost him over a grand to get it sorted, then another couple of grand in fines for discharging raw shit.

There’s 5 of us Inc 3 girls who are now 15 and 13, so it’s fairly well used!

Empty regularly or you’ll block up the soak away and have to dig a new one when your effluent gets noticed by someone who reports it to the environment agency (I used to pick up the phone and go and see what the problem was then enforce remedial action).

A long stick will tell you how deep the sludge is, when it gets to within a foot of the dip pipe call the tanker man.

when it gets to within a foot of the dip pipe call the tanker man.

^ this. Although we haven’t needed to empty yet, it will need doing at some point and you def don’t want to foul your soakaway.

I think they’re going to build somebody’s back garden in the field where I assume our soakaway might be – they will have some mighty long grass.

unless you own the field your soakaway should not be there …

IME (relatives) the appropriate behaviour is to do nothing in the way of maintenance and assume that it all works by magic rather than the cracked pipe letting untreated sewage soak straight into the ground under the garden.

worked in a care home, and they had a huge septic tank, thing emptied every so often, then to save costs wasnt, sewage then started seeping out into watercourse nearby, result, large fine, and bill for replacement septic tank, extra pumps and other warning systems.

Just wait for the visit from EA or NRW if in Wales

unless you own the field your soakaway should not be there …

I didn’t put the field there.

I presume the guy who built the house in the 1890s owned it. I don’t speak medieval so I can’t interpet where the deeds suggest it might go. It’s not on any utility drawings though, so that’s okay.

ah thatll be a fun conversation when they dig up your soakaway and you no longer have a soakaway then if thats where it goes :s

Not sure if you can discharge into a burn. If the tank discharges grey fluid you need to have some distance between the outlet/soak away and any water course. Fines are prohibitive!

We get ours emptied annually, and it costs around £130 for 1200litres, but it is the solids that need emptying, not the fluids. And don’t put fat down the drain – fat bergs clog up the pipes and stop it all working.

And now for the official version 😉

Septic tanks should – assuming they are sized correctly – be emptied annually.

HOWEVER

Yours is emptying into a watercourse. This is already on the grey area of legality as it is an old and existing connection, BUT in a couple of years it is going to change and become VERY illegal. Big fines and the like – I know in this part of the world they are starting to walk catchment areas to see what is out there. You will have two options which is put it to a soakaway (which will have to be constructed appropriately and shown to be thus, not just a bodge job) or put in a proper treatment plant and that into the watercourse subject to whatever restrictions are in place in your locality.

But right now… get it emptied. Then start working out what you are going to do with it before someone either makes you do it, or fines you a large amount of cash! It won’t be cheap either way… just so you know…. I am just pricing a similar one up at the moment and that is looking to be somewhere near £15k which I think may scare them off somewhat!

It soakaway is into a field, it’s in our deeds we pay an annual fee to the farmer. £0.25p per year.

The previous owners paid up for the next ten years or so.

It was just you said:

All waste water from the house goes into the tank and clear water comes out of the tank into the burn.

Which sounded like everything goes into the tank, and the outflow is into the burn 😉 If that is not the case, and it is going to soakaway, then you are grand! Just get it desludged now by a decent tanker company (by which I mean NOT *Serious) or a handy local farmer whom does such things (they are usually the best bet actually).

Depending on the size of the tank and how many people are using it you may be able to stretch out the desludging intervals from the suggested annual cycle to once every two, three or even more years! I know of a few where the tanks are massive and there are very, very few people occupying the house and it can take some time before they need looking at. What you want to avoid is too much sludge in the bottom and too much crust on the top – if the thick stuff gets into your soakaway you are screwed… or your soakaway is at any rate!

If you want more details – or chat about it – give me a shout. eMail should be in my profile somewhere 😉

Capt K

Many thanks for the heads up. What’s the time line for the changes in legislation?

I think breadcrumb isn;t the OP Capt.Kronos?

Unless he has multiple logins 😉

I’m the OP with a single login. No soakaway on our system – it discharges into the burn. Oh and we are in Scotland – not sure if that makes a difference re legislation.