[John]

We've never had a septic tank system before and we're getting conflicting information on them.  Some say to empty them every 6 months, some 2 years and some say if you run them properly (??) never!

So any info on them gratefully received.

[Mosslane]

When we moved in to the cottage the tank hadn't been emptied for quite a few years. We had it emptied last year and I doubt it will need doing for at least another 2 years. Ours is an old fashioned hole in the ground type with a natural soak away so I guess more modern ones may need doing more often.

[mumofstig]

there are different types. Some have a soak away/overflow that means with normal use they do not need emptying ( We had to have ours done once in 5 year period, when we had 3 friends staying, so there were lots of extra showers/baths and washing )

My friends had the other kind which retains everything and it needed emtying only when full (Obviously )........the timing depends of course on how much waste you are producing and the size of the tank

[Trillium]

The key for John will be to find out if the current homeowners know anything about the system - age, type, what kind of maintenance they've had to do, any problems, etc. And go from there.  Standard procedure for Cdn homeowners buying a 'new' house with a septic system is that the current owner must have the tank emptied and generally inspected by the removal company, or the lawyers won't allow sign off. Septics can be expensive problems for clients if there are hidden problems so lawyers are careful about this.
Ours was emptied before signing time, a small problem found and fixed, and I'm embarrassed to say that we haven't emptied it in 7 years and really should have it looked at, just in case. But then, we don't use much in chemicals which tend to kill off beneficial bacteria in the holding tanks.

[GrannieAnnie]

As there is only the 2 of us, ours doesn't fill up very often, we've only had it emptied 3 times in the past 8 years, but if you are very good about what you put in it e.g. no bleachy stuff, the little bugs should mean that it doesn't need emptying much at all if there is the overflow/soak away that Mum mentioned.

You could of course have one of the new treatment plants with reed bed etc, which will empty your almost potable water into your local dyke, drain, ditch or whatever.

I'd like the rainwater system which filters the water so you can use it for toilet flushing, washing machine, shower etc, but just don't drink it!!!  

[Gwiz]

At work we use a Klargester system. It was designed for use for up to 6 people, and under these conditions would hardly ever need to be emptied.
Usually there are around 30 people at work permanently so we have to have it emptied about every 6 months.

[ex-cavator]

there are different types. Some have a soak away/overflow that means with normal use they do not need emptying ( We had to have ours done once in 5 year period, when we had 3 friends staying, so there were lots of extra showers/baths and washing )

My friends had the other kind which retains everything and it needed emtying only when full (Obviously )........the timing depends of course on how much waste you are producing and the size of the tank

Kind of correct - those that have no outlet & need emptying when they're full are cess tanks, and are simply a storage facility. What I suspect you may have is a septic tank, which is more than just storage - it is a treatment facilty, using the cold anaerobic digestion process to treat the sewage and render the liquid portion 'safe' to discharge to groundwater, usually via a soakaway. A byproduct of the digestion process is sludge, and this will build up until the tank is full of sludge (and hence no room for the treated liquor). At this point, the tank will require emptying, although a little of the sludge should always be retained to 'start' the treatment process off again as the tank begins to refill (although folk will tell you that flinging a dead rabbit in does the job just as well).

How long it can go between emptying will depend very much upon the size of the tank, and the number of people it serves. Ideally it should be around 2 years, but if its a large tank and there's only a couple of you, it might last several years more. Whether or not 'grey water' e.g. bath waste & the like are connected, will make little difference, as comparatively clean water such as this will pass through the process with little effect on the sludge make - sludge is only produced by the breakdown of organic waste, so length of time between emptying is more dependant upon the amount of faecal matter, food waste, etc than volume (so don't use a food macerator when you've got a septic tank).

To determine whether it needs emptying, you really need to look at what's coming out - there's normally a kind of separator or 'interceptor' arrangement on the outlet, that decants off the treated liquor from above the sludge in the bottom but below the floating matter / fat & grease on the top. If this liquor is heavily laden with sludge solids then the tank probably needs emptying, and failure to do so will quickly result in fouling up / blockage of the soakaway, which will then result in unsightly flooding / nasty smells / a possible visit from the Environment Agency and a bigger bill to reinstate the soakaway than it would have cost to empty the tank.

Hope this helps 

[John]

Thanks ex-cavator - useful info there. We're (sort of) looking forward to finding out where the outlet / soakaway is exactly. We know it's in the front field.. somewhere.

[Goldfinger]

I work for a major plant/toilet/accomodation hire company and we do emptying of peoples tanks.

We come across many different types of tanks and agree with what people have said so far. As said, it depends on how many peoples effluent goes in and if it is just a tank or has an outlet.

We've come across tanks that need emptying every 4/6 weeks and some that only need to be done every 2 years!

[noshed]

Don't you need to be careful about what detergents you use etc?

[Goldfinger]

Oh yes, and that too about detergents and chemicals!  :blink:

We get told by the people that work in the sewage treatment works that, that is why it pongs.

People are using all these weired and wonderful all singing all dancing cleaners these days not realising that they keep working all the way down to the works where they need 'good bacteria' to do the 'treatment' work, (that also keeps the smell down), but is being killed off!

I'm not saying don't clean, but we should try and be a bit more, er, eco-friendly?

[John]

How do you know when they need emptying? I hope there's some way to know before the loo backs up! 

[Poolfield2]

Best to ask the people there when how often they have emptied it and that will give you the best idea for your system.

Ours is an old concrete one apparently but we haven't had to empty it in 9 years and has given us no trouble. You can tell where they outflow goes cos the grass is always greener To tell if it needs emptying, lift lid and check the level or if you're a wimp wait til it starts to overflow and send for the emptying man quickly and no it won't back up into the loo unless it is higher than the loo

Even if you have to empty it every couple of years I think it is cheaper than paying for the sewage disposal the normal way??

[Goldfinger]

I've seen some tanks develop a 'crust' from the top down over, and so when the crust starts to build up and cover/block the inlet, that's when I think you have to get it emptied.

[8doubles]

All this talk of emptying cess pits reminded me of the man for the job, the late Blaster Bates, who is available on youtube if you are not offended by colourfull language.

A Cheshire lad too.