Septic Tank full after 6 months

rob22

Hi All,

Was hoping someone could give some advice on a septic tank issue. Background is: We moved into house in Aug 2010 previous owners said tank had been emptied during summer 2010, however in November it was full, so we had it emptied. I've noticed that it appears to be full again. By full I mean backing up to inspection area before tank and rodding doesn't help. We try to limit the use of chemicals going into the tank.

I had a look at the setup and it looks like there are a number of rain water drains/gutters going into the inspection area on the percolation area side of the tank. From what I've read this isn't a great setup but my question is, would this cause the tank to fill up after 6 months.

also is it possible that the tank is too full of water so it looks like the tank is full, in this case would pumping the water out of the inspection area on percolation area side of the tank solve the problem?

Poor Uncle Tom

If the rainwater/cleanwater is entering your percolation area for the tank, this will saturate the grounds and it will not work properly, as is your case.

The cleanwater should be diverted straight away, the system has no hope of working properly until this is done.

If the installer directed clean water into the sewerage system like that I would be worried as to what else they have done wrong. You would be best advised to get your entire system looked at and evalued by someone on your Local Authorities list of indemnified site assesors and see what recommendations they come up with.

tred

Poor Uncle Tom wrote: »

If the rainwater/cleanwater is entering your percolation area for the tank, this will saturate the grounds and it will not work properly, as is your case.

The cleanwater should be diverted straight away, the system has no hope of working properly until this is done.

If the installer directed clean water into the sewerage system like that I would be worried as to what else they have done wrong. You would be best advised to get your entire system looked at and evalued by someone on your Local Authorities list of indemnified site assesors and see what recommendations they come up with.

Standard figure of 8 Tanks are notirious for water ingress if not isntalled properly, is it possibly its just full of rain water?.

mickdw

It is possible that the outlet from the tank is not suffiently lower than the inlet thereby meaning that once the fluid level in the tank reaches its max level (which it should do rather quickly) you will get up backing in the system.

Even with all the surface water being directed to the percolation area (connected in after the septic tank if I understand you correctly) or even having poor percolation in general, I would expect the tank to function reasonably without backing up but you would get smells and ponding in the percolation area.

Poor Uncle Tom

mickdw wrote: »

Even with all the surface water being directed to the percolation area (connected in after the septic tank if I understand you correctly) or even having poor percolation in general, I would expect the tank to function reasonably without backing up but you would get smells and ponding in the percolation area.

Directing the clean water into the percolation area provides for shock loadings which the percolation area is not designed to take. When the percolation area fills up, even temporarily, the tank can not function properly.

rob22

Thanks for responses, I took a look in the inspection area for the percolation , looks like there's about 2 foot of water in there, not really sure what that should be like normally though. I suspect that the rain water has had an effect on the tank backing up, was going to try a dirty water pump to see if that helps with the problem. Will get the problem sorted properly soon though.

mickdw

Poor Uncle Tom wrote: »

Directing the clean water into the percolation area provides for shock loadings which the percolation area is not designed to take. When the percolation area fills up, even temporarily, the tank can not function properly.

I agree that the surface water has to be redirected but it is still possible to design/layout the system so that the backing up/ponding/overspill happens after the tank by locating a chamber lid at a suitable level or whatever way you wish to do it. I find this is the best solution particularily in houses with soil stacks from upper floors. I much rather have a chamber overflow its lid at the percolation area - where you are dealing with partially treated effluent and a water like substance compared to having the entire system the house side of the tank block up right back to the house and possibly having all sorts of crap out on the footpath when opening chambers etc.
Yes this leaves an uncontrolled spill in the event of overload of the percolation area but overall, this setup allows the tank to operate in a very undisturbed way with no raising or lowering of the effluent in the tank which leads to much more satiSfactory operation (traditional systems) and treatment.

Ive seen it done too with a float switch in the distribution box which gave a warning in the house of the rise in level in the distribution box due to overload - still with the chamber overspilling before backing up the system should the warning be ignored.

ponddigger

hi rob did you here of a system called raised beds check it out .solved my friend tank. your sponddigger

BryanF

mickdw wrote: »

I agree that the surface water has to be redirected but it is still possible to design/layout the system so that the backing up/ponding/overspill happens after the tank by locating a chamber lid at a suitable level or whatever way you wish to do it. I find this is the best solution particularily in houses with soil stacks from upper floors. I much rather have a chamber overflow its lid at the percolation area - where you are dealing with partially treated effluent and a water like substance compared to having the entire system the house side of the tank block up right back to the house and possibly having all sorts of crap out on the footpath when opening chambers etc.
Yes this leaves an uncontrolled spill in the event of overload of the percolation area but overall, this setup allows the tank to operate in a very undisturbed way with no raising or lowering of the effluent in the tank which leads to much more satiSfactory operation (traditional systems) and treatment.

Ive seen it done too with a float switch in the distribution box which gave a warning in the house of the rise in level in the distribution box due to overload - still with the chamber overspilling before backing up the system should the warning be ignored.

:eek:hope there's no stream near where you would see this as acceptable.
OP just redirect the surface water.
to highlight how the council would view this: If you every have to go for planning for anything on your site, the first thing you'll have to prove is that your foul waste system works correctly.

BryanF

rob22, start by redirecting the surface water.
to highlight how the council would view this: If you every have to go for planning for anything on your site, the first thing you'll have to prove is that your foul waste system works correctly.

rayjdav

BryanF wrote: »

to highlight how the council would view this: If you every have to go for planning for anything on your site, the first thing you'll have to prove is that your foul waste system works correctly.

<SNIP>

To the OP. Is there foul water actually getting to your distribution box. I have seen with my own eyes where the 4" pipe outlet from the tank fell back TOWARDS the tank. Maybe Mellor can answer this but, I'm pretty sure even in Oz water does not flow uphill? Also, what would approx age of the system be as if it were done say under SR6 1991 or before, there is a good chance that there is no percolation area, just a single pipe going to a soakpit:eek: and given todays modern household usage, the tank just simple is not capable of taking the loads?

BryanF

rayjdav wrote: »

<SNIP>

<SNIP>

muffler

Can we stick to the topic here lads.

rob22

As far as I can make out, foul water is getting into the distribution box. The house was built in 1987, but according to the guy that pumps out the tank, previous owners never had an issue with it before, only needed to get it emptied once a year.

Will look at getting the water redirected and get someone out to have a look at the system, is there an easy way to tell if there's a percolation area?

99nsr125

rob22 wrote: »

Hi All,

Was hoping someone could give some advice on a septic tank issue. Background is: We moved into house in Aug 2010 previous owners said tank had been emptied during summer 2010, however in November it was full, so we had it emptied. I've noticed that it appears to be full again. By full I mean backing up to inspection area before tank and rodding doesn't help. We try to limit the use of chemicals going into the tank.

I had a look at the setup and it looks like there are a number of rain water drains/gutters going into the inspection area on the percolation area side of the tank. From what I've read this isn't a great setup but my question is, would this cause the tank to fill up after 6 months.

also is it possible that the tank is too full of water so it looks like the tank is full, in this case would pumping the water out of the inspection area on percolation area side of the tank solve the problem?

In Short

Divert rainwater/runoff away from septic tank

Check for water leaks into/beside percolation area

Empty tank again and check for backflow into the tank
from percolation area, if this happens and and it's ultra clear water
take a sample and test for chlorine if positive it's a busted pipe nearby
if negative it's groundwater and requires diversion drainage.

I'll pull out some sample videos if you want to know what that looks
like.

If no backflow diverting rainwater "Should" work

Let us know how you get on.






In a bit more detail

Older houses frequently had rainwater directed into the tank and
although frowned upon now and indeed illegal for new installations,
did work adequately for lots of people including ourselves.

If you have a septic tank you vey likely live in a rural or semi-rural
area, you had your tank emptied suggesting that you live in a one-off
house and maybe a half acre site (and not as part of a farm), therefore
the tank is fairly close to the house and percolation area too.

If the above is true any backing up in your case gets fairly bad fairly quick.

As previous posters have advised start by diverting the rainwater/run-off
away from the tank.

Domestic houses can legally discharge run off water/rainwater into the
council drains, so if that needs to be done provides a proper and long
term solution if needed.

Inspect the percolation area to see if the ground is saturated, however
rainfall has been very low in the last 6/8 weeks something of the order
of 30% below average so the ground should be quite dry.

If the ground is quite dry then the percolation area could be silted up
which is not uncommon.

If the ground is wet there could be a leak in mains supply nearby causing
the ground to become waterlogged and backflow into the tank.

rob22

Thanks for responses, I'll check for backflow into tank and will start by diverting rainwater and hope for the best.

Out of curiosity, would excess water in the tank cause the tank to fill up with solids due to the fact that it's not working correctly?

sydthebeat

rob22 wrote: »

Thanks for responses, I'll check for backflow into tank and will start by diverting rainwater and hope for the best.

Out of curiosity, would excess water in the tank cause the tank to fill up with solids due to the fact that it's not working correctly?

yes!

the septic tank works on the basis of anaerobic bacteria action breaking down the solid matter. This bacteria works when there is no oxygen present. A thick scum forms over the liquid to prevent aeration. If you have bursts of heavy oxygenated rainwater inflowing, then this scum cannot form and the bacteria die off. The tank becomes nothing greater than a holding tank then.

Rainwater should never be allowed enter a septic tank

muffler

sydthebeat wrote: »

yes!

the septic tank works on the basis of anaerobic bacteria action breaking down the solid matter. This bacteria works when there is no oxygen present. A thick scum forms over the liquid to prevent aeration. If you have bursts of heavy oxygenated rainwater inflowing, then this scum cannot form and the bacteria die off. The tank becomes nothing greater than a holding tank then.

Rainwater should never be allowed enter a septic tank

You know your ****

sydthebeat

muffler wrote: »

You know your ****

Imagine my conversations at a dinner party!!!

LoTwan

sydthebeat wrote: »

Imagine my conversations at a dinner party!!!

After dinner conversation yesterday was about my treatment tank & polishing filter. Your dinner table discussions wouldn't bat an eyelid chez nous :-)