[SafeHaven]

As we work through the contract for the purchase of our property, I had my solicitor ask the sellers when the last time the septic tank was emptied. Their answer was 1998.  They also don't know when it was installed. The property has been rented out for the last 18 years, so the installation would have been before this.

Is this normal? I've never had a septic  tank before. I don't know what kind of system it is either.

I've asked my solicitor to enquiry as to what type of system it is,  if they've ever had any problems, what maintenance they've carried out, etc.

I would appreciate some guidance on how to proceed with this. If anyone has any experience of buying a property with an older system, I would apppreciate some advice, what to look for, ask about, etc.

[regen]

Probably a better question would be how full of solids is it?  If the solids build up too much then they are flushed into the run off system and when this blocks it is very difficult if not impossible to clear.

Even if its emptied be fore sale its no guarantee it will work properly. It doe demand on the type of tanks and how efficient the drainage is.

More important is wether its been registered and where the run off goes to -some still drain into an open ditch which would be very costly if the authorities got involved!

Regen

[Perris]

we were in your shoes about 20 years ago; we were told by the vendor he'd never emptied it, after he had been told that it wasn't necessary by the builder of the house, when he sold it; the house and tank constructed in 1970. The house papers include a document about permitted runoff to a field below the tank. Once we bought, we had it pumped out anyway, which involved 3 trips by the disposal tanker, and we've never had it done since. We don't know how it works, but it does work (no smell, no apparent overflow, no issue in the field), and we follow the principle that if it ain't broke, it don't need fixing. Or, let sleeping dogs lie. 

[juliem]

 :My father had his septic tank built by a local bricklayer in 1960....and apart from the soak away getting blocked it's only been emptied twice.
My septic tank was buried in the ground in 1981 (it's the plastic light bulb type)  and I have this emptied every 2 years.Never sure whether it actually needs emptying but decide to take no chances.
It will depend on size of the household  of course and how careful you are with not using household chemicals on how quickly the solids are broken down by bacteria.
Buildings Regs have been tightened up now and I know that in my area the local authority will make you install some very fancy expensive systems with new builds.
There's bound to be a discharge point somewhere....if you tank is discharging raw sewage into stream/river the Dept of Environment can impose a pretty hefty finč

[SafeHaven]

So it seems depending on what type of system it is, it might not be too much of an issue that's it's not been emptied much...?

It's a 3-bed house so I would assume it's a reasonable sized tank.

I don't know much about the previous residents, but me and my partner are strictly natural products. Bicarb and vinegar are my go to cleaners, soap nuts for the laundry, Dr Bronners in the shower... I even make my own toothpaste!

[SallyintNorth]

I'm nothing like an expert but I'm sure I've been told that some of these systems were designed so that they shouldn't need to be emptied.  So yes, I'd be happier to hear that it's never been emptied than that it was emptied in the last few months.  Of course I'd have a walk around downstream and downwind, checking for deposits on the ground, smells, etc.

It's not just chemicals that are an issue.  Sanitary products also cannot be flushed.  I don't think they harm the tank, per se, but they tend to get wedged in the pipes and cause blockages.

[SallyintNorth]

Hmmm.  Went off to do a bit of googling, and there's a lot about how people wait until there's a problem and how that can be TOO LATE.  :/

This page from Southern water was particuladly helpful.

[bj_cardiff]

I asked the seller to empty the septic tank when I moved into this property 10yrs ago but haven't ever emptied it myself. I think all your solicitors inquiry will do is cost you and the answer will be that the vendors don't know. As with most things, if you get an 'expert' to take a look they'll tell you that its not up to modern code and will cost £xxxx to bring up to code. Of course it doesn't need to be up to modern standards to work properly!

I'd probably use it as a barganing chip and ask the seller to empty it before the sale completes or to reduce the cost by xxxx to cover the cost of emptying it.

[juliem]

The government did decide a few years ago that all septic tanks had to be registered and the idea was you would not want be able to sell your property without the paperwork.Then for some reason they abandoned the ideą.perhaps they decided it was unworkable.
Had mine emptied yesterday...every 2 years cost £140.
The cost  is creeping up so it pays to be very careful what you put down the drains.
My neighbour with a new build was made to have a very fancy system...cost thousands.

[henchard]

Septic tanks are very simple. Comprising usually of two (or three) separate chambers. There are old brick ones and modern fibreglass ones.

Effluent flows into the first chamber where a natural biological breakdown occurs and solids settle out to the bottom (and a nice crust floats on the top!). The liquid component flows into the next chamber where further breakdown occurs before the liquid part exits to land drains. This semi treated effluent then filters through the drains and soil for a final 'polishing' before entering the water table. The solids need emptying at regular intervals which depends on useage and tank size.

You can see from this that there is no magic and as your poo has to go somewhere it either settles out in the tank and if it's not emptied starts to fill it up and then the associated land drains leading to expensive repairs or often is allowed to seep via the land drains (often on purpose) into a local ditch or water course; this is often identified by a nasty black slime. This is illegal and unpleasant but not uncommon.

Just for the record land drains laid in clay soils do not generally work well anyway and aften illegally fed into watercourses.

So if a tank hasn't been emptied for 20 years there is almost certainly an issue somewhere as poo does not just evaporate!

I empty my modern 'onion' fibreglass tank about every 18 months or so.

[Perris]

Indeed pooh doesn't evaporate, but it does break down. We have no slime, no smell, and no other issues.

[henchard]

Indeed pooh doesn't evaporate, but it does break down. We have no slime, no smell, and no other issues.

Matter is neither created or destroyed. It does indeed breakdown into solids and liquid as I said above -,the liquid element does flow away but the solids do not, that is the whole point of the tank. The solids fill the tank and if not emptied the associated drains. You may get away with not emptying some old tanks for a good while particularly on very light soils. Eventually they will clog up if the tanks are not emptied. Faeces does not magically become water by some biological process, not does hair, skin cells, toilet paper, coffee grounds, fat and food waste or anything else that you decide to flush or wash away.

I was an Environmental Health Officer in another life and have served many, many statutory notices on owners of detective septic tanks over those years!

I hadn't read this when I wrote my advice but you'll see it echoes what I said

https://www.wte-ltd.co.uk/septictank.html

[Perris]

I don't doubt your expertize in this area, and the link was interesting (I guess we're in the point 3 category) but a government site would be better than a commercial one with a vested interest in selling new systems.

Anything organic (e.g. hair, skin cells, and coffee grounds) breaks down, and toilet paper is designed to too. We put food waste in the relevant recycling bin, and don't flush sanitary products of course. I am also light-handed with antibacs and bleach in household cleaning, preferring vinegar e.g. For what it is worth, the story we were told is that the system was started with a dead sheep - a whole one, to provide the relevant microbiological soup to break down whatever else arrived in it. I appreciate that solids do not magically become water, but they don't stay solid; graveyards wouldn't be full of just bones if the other body solids didn't liquify.

[stufe35]

The septic tank at my dads house has been emptied twice since he bought it in 1978.

At my own house I emptied the tank the year I moved in as was unsure how it would perform. Since then I have lifted the lid once a year and given it a stir with a stick to check it is nice and fluid. It always has been and weve been at our place ten years now.   The tank is nothing more than a brick built chamber about 1.2 m x1.2m x 1.2m. It over flows into a net work of pipes/ soak away in a field. There is a mesh grill over the outlet to stop toilet paper or whatever escaping before it has broken down.

My dads set up is similar except the tank is huge.

[regen]

"but a government site would be better than a commercial one with a vested interest in selling new systems. "

You must be joking! Are you referring to the same government who said that all the external cladding fitted to high rise buildings was safe until they actually,after the event, checked and found most of it was not!

It is quite possible that a well designed and possibly oversized old style cesspit (not a modern Onion) will come into balance if used very carefully where it can last for years without being emptied. You are right that all ORGANIC material will,under ideal aerobic conditions, break down and most will be converted to co2 and water. However the breakdown of the more complex carbohydrates like lignin in toilet paper will take much longer and of course any inorganic materials like soil from veg washing will never break down.- the time taken to fill the tank with solids is directly proportional to the volume and quality of the material added.

The original poster was looking for an answer based on the average to poor situation not an ideal situation where the system is under used,never gets any inorganic solids added and is free from any chemicals which interfere with the digestion process. In the average situation it is advisable to check the tank annually and have the solids pumped out if they are within a couple of feet of the top. Any signs of liquid back up in the drains pre tank indicate that the drainage system post tank is blocking or the system is not big enough .

Regen