andywally

Hello All

Potentially we could end up in a situation where we need to install a septic tank, I say possibly as we havent bought the place yet, I need to understand and cost out a few issues first this one being potentially the biggest one, the only thing is there will not be any access to have it drained mechanically due to being at the end of a tight/narrow winding path, so my question is has anybody had any experience of tanks that do not need to be desludged ? now assuming that you understand the chemistry behind what is occuring (and to a degree I do) then according to some people this is indeed possible, however the advice online varies wildly (as per usual) some people who are in the trade saying entrely different things ie; desludge it every 2-3 years and some people saying they have run a tank for 40 yrs and never had it desludged, I know this can be infuenced by the amount of people in the household, the size of the tank/leach field or filter and understanding the process that is happening in the tank and maintaining that process as best you can.

So has anybody had any experience of such things ? even better if you have had a 'mini sewage treatment tank' with an aeration chamber installed and if so did it 'sludge up' ?

Bit of an obscure one I know !!

Moses2013

Can't comment on Portugal but in Ireland people know a lot about the septic tank. Just like some people might never change oil in their car and say the car still works, I wouldn't rely on that statement.
Portugal is in the EU and I'm sure you have local regulations, so could be faced with hefty fines if you don't comply. There are other alternatives, like turning poo into power https://www.loowatt.com/

BillBullock

My septic tank has been functioning in the Algarve since 1996 and has never needed to be emptied. I was the first person to open up the inspection slabs which were sealed with cement and all I had to do was remove the wet wipes that were floating at the top of the fluid in the first tank. You have to be careful what you send down to the septic tank and educate your visitors; it seems that a lot of people flush all sorts of things down the WC.

macliam

My septic tank in Portugal has never been emptied in the 9 years we have owned our place, nor AFAIK in the 8 years of previous ownership.

As it was installed by the previous owner, I have little idea what it is, apart from what I can see - and it is a large, modern plastic tank with two inspection covers, buried almost entirely in the ground. It has caused no issues - but then there are only two of us there, not full time and we are relatively careful with the products we use and what we flush away. My greatest fear has been that it would be damaged when our aceiros are ploughed each year..... but the tractor drivers are smarter than they sometimes appear to be!

I have avoided the temptation to open it, because I fear that UV exposure will have caused degradation and damage that I would rather not provoke, unless there is no other option. One of the covers is cracked and I feel certain it would split were I to try to remove it - and I don't know where to source a replacement. However, I also fear that the tank itself might crack if I fiddle with it - so best left alone! This isn't something I find easy to do as it becomes a known unknown, but we are where we are. However, whilst I'd rather avoid the trouble, disruption and cost of interference with it, it is replaceable and accessible.... so I would be concerned in the position you have suggested. But, how will you install the tank if you choose to do so? Are you talking about a commercial unit or a self-dug and constructed version?

In Ireland, my small factory was based in an old National School and had a brick-built septic tank, which appeared to be little more than a buried, brick-built chamber serving the two toilet blocks.. Again, I was only there for 2 years and had no issues and although I asked some locals, nobody recalled it having been emptied. I did check it and found that it appeared to have significant capacity spare.... so left it well alone!

So, will any tank last forever without being emptied? I have no idea, but mine in Portugal has been trouble-free and maintenance-free for 17 years.

liveaboard

As others, I had differing advice...

First, you should know that septic tanks need a permit from the local authority.
My place already had one, but I put in a new tank and drain field.

Drainage has to be checked first, some land doesn't drain and a septic tank can't be installed.
There are rules about proximity to wells, other property, and more.

Mine does not seem to sludge up; I've checked it once or twice over the years.
Not flushing toilet paper down might be a big help.

Alan PT

It's possible, depending on the situation, that it could be accessed. We had a septic tank in the UK that was down a fairly narrow windy road, with a very sharp turn at the end into our 100+ft driveway. They just put a note on our file to send one of their small vehicles with a couple of extra hose lengths to go down the driveway. Tractors also often have tanks and pumps for spraying slurry, that might provide an option if it's really inaccessible (not suggesting you spray it once emptied!)

AFAIK, in any system, if you do nothing to clear the sludge then eventually it will fail and unfortunately sometimes (especially in drier parts) it might not be obvious that you are effectively discharging raw sewage to your soakaway. Depending on your use and how careful you are about what you put in there, it could take a long time (many years), but it's hard to tell without poking around in there!

Something to consider - would you even get permission to install a septic tank if there's no way to empty it?

andywally

Ya know some of you guys are f***in priceless.......(and I do not mean that in a sarcastic way btw, genuinely priceless) .........I never considered the permission/license issue dependant upon 'is there a way to empty it' or 'proximity to a well or a watercourse' ..........the fact is the house runs alongside a stream in the bottom of a valley, so the leach-field might be an issue (permission wise) ergo maybe the 'aerobic mini sewage treatment system' which pumps out water fresh enough to put into a watercourse (apparently) but maybe still needs de-sludging occassionally and if it is accessible to be pumped with extra long hoses ? more questions than answers guys (questions that hadn't occured to me btw) Muito Muito Muito Obrigado for your input.................if anybody is remotely curious ? I will post the result/outcome of said questions when I can answer them. .

macliam

Please do - it will make a pleasant change to have someone post an outcome...... and will be of use to all of us.

Pulaski

It may be more than just a permission issue. If the proposed site is close to (vertical distance, as much as horizontal) a stream, any other body of water, or even just low-lying land, the drain field might not drain adequately (US speak: "perc", short for percolate), as wet ground and/or a high water table will interfere with reliable drainage.

My home's septic system was originally installed with a secondary tank to collect out-flowing liquid, which is then pumped periodically up a bank to the drain field in a clearing in the trees that was cut primarily for that purpose, where low-lying, waterlogged ground was less of an issue. ..... I say "less of" because 2017-2021 were incredibly wet and the ground, even sloping land got super-saturated with water, so several neighbours including some that were actually up-hill from my drain field, had varying degrees of septic tank issues, with localized "sewer" smells in the areas of their drain fields. I know at least two neighbours had their septic tanks pumped, including the one down-hill from me, but the rest of the problems went away as the rainfall reduced to more reasonable amounts in the second half of 2021.

Alan PT

It was also nice that you started already armed with some information from your own research, makes for a much more interesting discussion

Sadly the person who bought our house in the UK did not do his research... At a late stage in the purchase (we were already in Portugal) we had en email from the estate agent. Apparently our purchaser had (without permission) gone to the house, taken the lid off the septic tank, had a stir around and pronounced that it was "full of liquid and quite unpleasant!"

He wanted to get it emptied. Told them that if he wanted to waste his money then he could go right ahead!

liveaboard

Better not until the sale is complete; the tank could collapse if it's left empty!
After pump out, the tank should be filled with water.

andywally

We are up in Seia visiting the house this weekend............. so I may have some answers when we get back on Monday, leaning towards a 'mini sewage treatment works' seems ok price wise and the only thing that comes out of it is water that is clean enough to eject into a watercourse (apparently) ..........then needs desludging from time to time, so the access needs to be resolved before we part with any spondoolies I sense a few bumps in the road maybe :-)

macliam

If access really is a problem.... might it be possible to pre-install the means to empty the tank? Just thinking of the top of my head here.... Access at point 1, connector to pre-installed tube running to point2, connector for flexible piping at point 2 to reach tank (therefore adding some fixed tubing in the middle to extend access). There would be a dimunition in the suction available at the tank - but I don't know if this would be a blocker or just require a more powerful suction at point 1. There M U S T be an answer!

andywally

Here's hoping so (there MUST be an answer) hopefully not a 'bucket and spade' though keep ya posted when we have paid a visit, we have placed a few offers to ascertain the sellers acceptability of negotiating, this was to make it worth while conducting the actual trip, as it is an 800km round trip, and it seems that it might be worthwhile paying a visit, then it all depends upon the layout of the land/house.

I fully expect the ground to be that wet that it does not drain efficiently enough, a 'percolation test' is to be done this weekend whilst we are in the locality.....when I say 'I fully expect' that is due to the fact the house is near the bottom of a valley with a stream nearby and the nearby land appears to be terraced on the 'as was' slope.........so I assume (rightly or wrongly) that it should be wetter further down the valley ? .............hence leaning towards the 'mini sewage treatment works' if somebody had actually had any experience of such a contraption then that would be 'formidavel' but I am getting the feeling that we may be the local guinea pigs so to speak..............ergo then maybe 'local experts' if it works anyway !!!............keep ya posted.

Pulaski

There are theoretical ways that you could pump out a tank at some distance, but the limiting factor is the vertical rise from the septic tank to the pump (presumably on the tanker lorry), which in practice is about 20ft/6m when the pump is "sucking" liquid up to where the pump is located (in theory it's about 32ft/10m, because pumps can't suck, it's actually atmosphic pressure). So the solution is a pump at the bottom of the rise pushing the liquid up, .... but that isn't very practical as that isn't how AFAIK septic tanks are emptied.

Assuming for a moment that the septic tank company doesn't have a demountable pump that can be taken down to the septic tank and used to pump liquid up to the tanker then an "if all else fails" solution, albeit a bizarre one, would be to have a second "holding tank" installed close to where the septic tank company can get their tanker lorry, then pumping out the main septic tank once every few years, ahead of the septic tanker lorry coming to collect the tank contents, which assumes that the tank is robust enough to be allowed to stand empty for years at a time (I have to say I have never heard of "collapsing septic tanks" being an issue in the US, and we certainly don't refill ours with water after they have been emptied.) And before anyone says "that's just crazy", that is not too far removed from my own septic tank set up ..... waste drains into the tank, but requires a pump to get the liquid up, about 20ft/6m to the drainfield. The biggest difference is that my pump operates on an on-going basis, not just when the tank needs to be emptied, and my auxiliary pump is, AFAIK, only rated for liquids, not everything that is in the septic tank.

So if there is a mini sewage treatment works option, that is likely preferable to the alternatives which would at best be considered "eccentric" and more realistically be a PITA to manage.