Jump to content
19 replies to this topic
Posted 2012-11-28 15:01:22
My house has septic tanks & after heavy rain the toilets will not flush for a few days. The tanks have been pumped empty & still the same problem. Does anyone know the cause / solution?
Posted 2012-11-28 16:17:33
The cause is the level of the water table which has obviously risen to the level of the top of your septic tank. Normally the water in the tank should drain away into the soil whilst the solids are kept inside, with the recent torrential downpours we have been experiencing the ground is now so waterlogged that there is nowhere for the water in your tank to drain away. When I've had the problem in the past it has just been a case of waiting for the dryer weather and it goes away by itself. I believe there may be a more drastic solution involving installing a drainage system for your property but have never investigated this.
Posted 2012-11-29 10:51:05
I have the same problem....gmac's reply is correct. When we had the "septic tank" installed I insisted they put cement at the bottom to seal it to prevent the waste from leaching out...the builders ignored my request & the bottom of the tank is earth...thus water from water soaked ground enters the tanks...I just wait it out. I found that using a plunger does temporarily help the problem.
Posted 2012-11-29 12:04:27
Interesting topic. I had this problem for the first time during the heavy rain yesterday afternoon. The toilet in the bedroom was suddenly very slow to drain away, so I thought that either the septic tank might be full or else the groundwater was so high that it was preventing it from draining away. The odd thing was that the toilet attached to the living room worked fine, no problems at all. So I figured that it can't be a septic tank problem, it must just be a blockage in the pipe somewhere. So I got out the plunger and after 5 minutes of pulling and pushing everything was back to normal, as far as I can see it must have been a blockage rather than the groundwater level, as it was still raining cats and dogs outside.
Posted 2012-11-29 16:23:13
Your problem could be a full or clogged seepage pit. Septic tanks should be connected to a drainage (seepage) pit which is where the grey water from the septic tank goes. If that is full your septic tank will be full of water and the toilets won't flush.
These seepage pits are normally constructed with 6 or 7 concentric concrete rings with holes in the them to allow the water to drain into the ground. If the ground in the drainage area is waterlogged then the pit won't drain. If you do have one of these pits, you can get it emptied out for about 500 baht, which will buy you some time. After awhile these pits can become clogged with lint (washing machine) and other effluent and fail. If yours in on the verge of failure, then it wouldn't require much water to push it over the limit. I have this problem.
Posted 2012-11-29 16:50:10
Apologies for my complete lack of knowledge on this matter so hope you don't mind responding to the following. Recently I had had all the tanks emptied & as soon as it rained the toilets would not flush and had to wait a few days before they were usable again. So how do you resolve the issue? Does it require the seepage pit tanks to be dug out and relined/re-connected to the two septic tanks? This is not a problem as I have a few Thai guys who could do this work. I assume the washing machine & kitchen waste water plus shower water drains into the seepage tanks and not the septic tanks as no issue for the water drainage; is this correct? Thanks for any guidance.
Posted 2012-11-29 17:00:47
When you have
Do you have a seepage pit tank with concrete rings that can be emptied. Did you have this emptied?
Not all drainage fields are the same. Some cannot be emptied. This is what I have so I'm thinking that maybe you have the same. I see these type of pits being put in all around the area where I live.
It's all the effluent from the kitchen, showers and washing machines which renders these pits useless after time. This effluent shouldn't go into the drainage pit, but that's the way the seem to do it here. My drainage pit doesn't work properly. I had it linked to another pit which drains well.
Edited by tropo, 2012-11-29 17:01:28.
Posted 2012-12-02 14:43:48
Quite "normal" problem many places in Thailand - it may disappear a couple of days after heavy rain stops.
If you have a proper septic-system, it shall be of two tanks, one septic and for draining the "cleaned" water into the ground.
You can empty the septic tank, which is always good to do sometime, but if it's raining a lot, the water in the second tank cannot drain into the ground, caused by the instant high level of ground water.
Make sure you have a working bacterial culture in the septic tank, so "everything" converts to floating/"water" - may need extra/new, when you pump the tank(s) empty.
Posted 2012-12-02 14:46:45
Thanks - how do you make sure you have a working bacterial culture in the septic tank and if a problem what agent can you use to rectify the issue?
Posted 2012-12-02 15:31:17
Had same problem - the sewerage drained into so called septic tanks that were not sealed - seepage tanks instead of septic tanks. As the water table rises so does the level within the tank - tried the suction truck and by the end of the day the tanks were full again. For kitchen water I have installed a grease trap - no matter how much discussion we have as a family I simply cannot get people to stop washing everything down the sink - at least the old oil from the wok goes out to compost these days. The grease trap needs emptying avery 2 weeks - a job I enjoy watchinbg my sons do as they are major contributors to the contents! So I am now installing a 1600 litre black plastic egg shaped septic tank - with baffle, vent and pump out holes. This collects the solids that get 'eaten' by friendly bacteria. If the solids ever build up too much I will get it sucked out THB250 per tank. I think this will be after a few years. The fluids overflow into a seepage tank (5 concrete rings in a tube) which then overflows into a 2nd identical seepage tank. Laundry drains out to water the lawn. The black septic ball is one of the larger sizes as we have 3 toilets and showers. It costs THB5,450 from global house. Smaller ones around THB3,000 (some peoople maker them with concrete rings but do not seem to have the 'baffle') Grease trap was about THB450. Larger sized pipes are preferable and incorporate some inspection openings. This topic is covered in the DIY housing forum.
Edited by linno2, 2012-12-02 15:33:26.
Posted 2012-12-02 15:52:35
Unfortunately nothing is "proper" around here unless you do it yourself. Effluent for the bathrooms and kitchen (including the washing machine) should not empty in to the seepage pit. It should go into a septic tank. A more advanced system has a separate tank for the washing machine, because the lint eventually clogs the drainage fields.
Posted 2012-12-02 18:12:24
Yes, I'd like an answer to that question as well please.
The house I live in had only been occupied for around 18 months before I moved in, but already the septic tank was full and I had to have it pumped out. A friend has told me that in four years he has never had to have his tank pumped, so I am assuming that the bacteria in my tank are long gone. When they opened it it was full of sh*t, not the bacterially digested stuff that I believe one would expect. So I would like to get a new bacterial culture put into the tank, how do I get that done?
Posted 2012-12-02 18:23:48
100% full of shit - no water? That's hard to believe after only 18 months. You guys must shit a lot.
If the water is not flowing into a drainage field, the toilets won't flush. That was my problem. There was only a small amount of shit in the septic tank.
I was shocked to discover that the septic tank grey water drains into the street sewers in most areas of Pattaya - and then down the sea. That's why we can smell sewage all around Pattaya.
When I got the guys over to empty my septic tank and seepage pit, they suggested that I drain the water from the septic tank to the outside sewer because my seepage pit wan't working. These guys were city council workers.
Posted 2012-12-03 15:15:07
»Thanks - how do you make sure you have a working bacterial culture in the septic tank and if a problem what agent can you use to rectify the issue?«
I am not an expert in that, but normally you can buy a bag of bacterial culture in a building market, like HomeMart, or a local store, drop it a bucket of water to dissolve and then directly into the septic tank. That is what they do, when installing a new septic.
If you have two tanks, you may be able to add bacterial culture in the drainage tank also, to avoid a heavy layer on the buttom of the tank, slowing the water darin into the ground. There is a 1kg can bactiral culture available for sewer tanks at HomeMart. I don't know if anything happens mixing different kinds (brands) or if they all are more-or-less the same. I regulary use the small 100g packs from Bionic G-001 (49b at HomeMart or HomePro) to liquify, keeping the pipes clean and tanks working. Just drop a bag in a toilet and flush.
Bionic G-002 is for grey water (kitchen etc.), dissolve grease and keep pipes clean. Can be used in grease traps. Both are non toxic, non pathogenic and invorormentally safe. You may find more info at www.micro-biotech.com (I have not checked yet).
Best to separate black water (toilets) and grey water (kitchen, shower etc.) into two tanks/systems.
Edited by khunPer, 2012-12-03 15:20:52.
Posted 2012-12-09 05:36:00
In the good old days, one would just drop a dead chicken (or cat, or other full carcass) into the pit to revitalize the organic breakdown. That assumes you have access to the tank/pit from above, and ready access to a dead animal. Personally, I Like the idea of a 1kg can of eco-friendly bacterial culture that khunPer mentions.
Posted 2012-12-09 07:34:20
After speaking with a Thai neighbour who is an engineer, who agrees it's caused by ground water seepage. I have decided to have the existing septic tanks for toilet waste dug out and install concrete base & rings for sealing the tanks. The grey water holding tanks are OK. Reason for doing so is moving overseas for a few years & renting out the property - do not want any complaint from tenants. Total cost for two septic tanks and labour 20k baht from Thai family who are in housing construction. Will also use the starter bacterial culture.
Thanks for the tips and suggestions.
Posted 2012-12-09 08:43:17
We also have this problem. The way you go about rectifying this problem depends to some extent on your specific circumstances, e.g. space available in yard, how well your yard can shed/absorb rain water, whether your yard gets runoff from the street of neighbours yeards, ground levels relative to street drain system and between toilet and top septic, etc. As one poster has mentioned, one approach is to remove the standard concrete tank (that lets in ground water) and replace it with something more sealed ... if you can get in to do the work. Of course all septic have some point where water can get in ... remember that in really heavy rain events some people will have water pooling above ground that might enter through a ventilation opening. If this combines with rain over preceding days (elevated groundwater level) then you have a real problem. In our situation we have limited options and during very wet periods we have to use an automatic submersible pump system to remove water from the top of the tank and put it into a PVC stormwater line that we installed .... this runs to a large nearby paddock. We already have seperate grey water tanks but this does not help enough to prevent the problem occurring.
Posted 2012-12-14 00:45:44
The top of a septic tank and it's drain pipes or lines should be lower than the plumbing in the house. There should be at least 1 inch of fall for every 10 feet of run in the pipe slope to assure water flow. If this is done, the septic tank will overflow onto the ground before the plumbing in the house stops up. That isn't a pretty sight either, but the ground will eventually absorb and break down the mess.
Using too much bleach will kill the organisms in the tank, but a reasonable amount won't because it will be too diluted. Also, bleach breaks down fast once exposed to air or water. I'm all for inoculating the tank periodically with the powdered stuff for that purpose. You can flush it down a toilet to make it easier.
If you have a high water table and are determined to have sanitary sewer, you import a pile of good permeable dirt and make a large pile. That would be about 20' around and 10' tall. You would install your septic and drains above ground in that. Then your house drains would go into a small sealed tank with a float valve and automatic trash pump which would pump everything up into that elevated septic system.
Posted 2012-12-18 02:26:34
I used to have similar problems. The earth surrounding the two concrete tanks is nearly 100% clay, so no real seepage in or out. It filled up fast, especially with visitors, or lots of rain.
We dug out one side of the tank area, cut a trench about 60cm deep and a foot wide and 10-15 meters long, poked a hole in the first tank about a foot from the top, filled the area and trench with medium crushed stone up to the hole we poked, put a 2" dia blue pipe about 5+ feet long from the hole and down the trench, filled all with stone to within a few inches of grade, topped with clay/potting soil. Not a very big leach field. Transpiration from surface plants seems to be enough to use up the flow from the tank.
The system hasn't backed up, or filled with water since. We pump the poop now and then instead of pumping out water every week. I guess depending on the grade of your property, it may work, but if the whole area becomes a lake, all bets off.