if its damaged, you now also have to replace the leech field iirc. which is where the cost comes in.
i believe i have this correct. i have heard of numerous ppl who have had quotes in the 10k range.
If what is damaged? The tank? Well if the tank is damaged from wear and tear, not extenuating circumstances, then it is standard to replace the entire system including the leech field because the entire system is probably worn and out of date. The leech field isn't the lions share of the cost in a septic system, it's the tank and the labor.
I guess I could see a septic system costing 10K for a brand new system built and installed from square one, but that is still a ridiculously high cost. The cost of 10K will get you a top of the line 4+ bedroom septic system designed to last an easy 20 years, but is still on the extreme high end of cost. A septic system that costs over 10K has some special circumstances surrounding it, or is just a flat out inflated cost. I know how much these things cost from having to pay for them and from reviewing builders/contractors specifications/build contracts on a daily basis for my livelihood, so trust me.
I have never seen a cost to install a septic system, even the largest and highest quality, ever reach $10,000. There are special septic systems required for certain terrain, land location and soil types. One of them is called a Mound system, which can run between 5K-12K, tops. Two other types are called recirculating gravel/sand systems and a Wisconsin at grade system, both of which cost between 5K-8K.
The most expensive and complex system is called an evapotranspiration system, which is a pressurized system that is used in very specific locales where the soil cannot absorb the fluid and runs a risk of contaminating a shallow water table. These systems are complex and expensive and utilize all of the standard septic system methods, but under directed pressure. They can cost up to 30K.
The average cost of a septic system is under $10,000 for the vast majority of homeowners in this country. Doing a few minutes of research and pulling up two build contracts from new constructions near the NY/NJ border I observed that the cost for one was 8K and the other was an astounding 26K(for a specialized system that was located directly on a lake)! Now the general cost of costruction has to be taken into account for that area as well. It looks like the cost to build in that area averages $300/sq ft, easily.
Sorry for the long and boring post about septic systems, but I had to clear this up.