So, about a week ago, our septic tank gauge ended up on the full mark. (The toilet no longer would flush.) So, we had to empty the water from it. Wait. Let me start with, we have two toilets on this property. We have a "Khmer style" toilet, bamboo and wood construction, semi-private, no running water, wash-by-hand kind of situation. Trust me when I say none of us here would like to use this one - unless we were in a really bad way, and it were the only toilet within 10,000 kilometers. Then, we have the more "westernized" toilet we had built a few years back, to accommodate - well, ME. (Well, truth be told, the Boss and her mom also use the facilities.) It is much more convenient / comfortable for a westerner. Water pump providing pressure, bum gun for that morning fresh clean feeling, and tiled walls and floors, for an aesthetically pleasing environment. It still has a manual flush toilet, though - no water tank. Fill a dipper and pour it in to flush. Simple. This was, primarily done to save water consumption. The "Khmer style" toilet was built and associated septic tank installed, oh, 9 years ago? That septic tank has never, not once ever, been opened. Our toilet, and associated septic tank, was built about 5 years ago, located about 50 - 60 meters away from the first one, and in the same soil - err, clay. To date, we have had to "pump" out the newer septic tank three (3) times. Two of those times have been within the past month or two! Here, they do not use any leach bed pipe to construct drain fields. (They have no idea what a drain field even is.) Basically, dig a round hole and add gravel to form the base of the tank. Then, they layer concrete rings, each about 1 meter in diameter, one on top of one another, typically about 4 or 5 in all, with cement in between. In the top ring, they knock a hole in the side for the sewer pipe coming from the toilet and cement it in. (Body / Gray water from the shower drains elsewhere, so as not to add to water flowing into the septic tank.) On top of these rings, they cement a concrete formed lid, with a 19mm (~3/4") vent hole in it. Anyway, my question is, has anyone here ever had a septic system installed in ground that was mostly clay? If so, how did you help the water to filter into the ground? Obviously, it does not drain fast enough through the bottom of the tank, for the volume of use it is currently getting.