Ive been thinking about getting one of those plastic septic tanks. Ive seen some and they look pretty good. The ones Ive seen, all have the outlet running out to the gutter in the street. (could explain some of the bad smells around Thailand)

I live out in the countryside and there is nowhere to run an outlet pipe. My question is, would a leachfield work here? I would imagine it would have to be at least a meter deep so it wouldnt be affected by heavy rains. Ive put in a number of leachfields in my day and the house I own in the US is still operating well on a drywell I put in about 20 years ago.

I made a leach line in the form of a square about 5 meters on a side around the tank out of 3" perforated PVC and fed with a Tee. It's buried in a 50X50cm trench filled with gravel then sand with a sod top. I actually put in 2 separate systems on each side of the house with kitchen/laundry/toilet into one and 2 full bathrooms into the other. No problems yet for 3+ years.

I built our leach field in a straight line 1 meter.deep X 2/3 meter wide X 7 meters long . It is essential to have a a drainage field in the system. It should also be 30 meters from a well so you do not contaminate the fresh water. As long as the soil will except draining water to leech the water going in the drain field you should be in good shape.

Jazzman on 'the other' rather cool site has several good images of his system, tho not to the degree that would guide you or me step-by-step. He is quite generous, and polite, with his advice, unlike spaceman.

Unlike coolthai no one here is a vendor selling products. I have seen the site & it does offer some good insights -but mainly it seemed to be based towards you using the 4 experts service. On Thaivisa just about any of the posters will provide you with a step by step (pictures included) Free of charge. You will also get a much better idea of the hidden charges & cost increases throughout Thailand. One of my acquaintances has been using coolthai & is already close to 400,000 baht over budget & not 1/4th done yet. No one can beat this site as it is made up of many oppose to an expert in his or her field. That way you get many views & experiences on the same subject for DIY repairs or basic construction.

We took the other road and dug three holes, 2 of which contains 3 metres of concrete rings each, and one with a similar plastic container as tatom´s.

They are all connected, but greywater goes straight to one of the concrete containers while toilets first go to the plastic one. This way we can do a coarse separation that makes the collectors happy. I dont know, nor really have any desire to know, where this stuff ends up, but they seem to have a couple of alternative dumping sites, as they like to separate the heavy stuff from the lighter.

Septic_Tank_Design_and_Construction.pdf

Thank you VERY much for the download- exactly what I have been searching for.

I take it you guys are all American??? by leachfield i presume you mean what i would call a soakaway??

The septic tank, often called a digester here in Thailand, an Onion in some parts of the UK, is a bacterial breakdown system, if it is working properly then the only run off should be excess water (the solids being "digested" within the tank) and that can go to what i would call a soakaway. Yes you can do it with the concrete rings but that gives a very small surface area to "soakaway", in the UK if we were building a house and there was an excavator / backhoe on site, we would dig a big hole and fill with stones and re cover, all run off water would go this route, this method is foolproof and lasts for years (10+) .

You may need to search around your site to find a free draining area suitable for a soakaway / leachfield, i have heard people complain that their soakaway is not working, only to find that upon inspection their builders have "washed" all their cement mixing equipment into the nearest "hole" thereby sealing the bottom!!!

Good luck and Happy New Year!