Hi Everyone. I'm in need of an unbiased advice about my septic system. When heavy rain or fast thaw hit, water backs up from our septic tank into our pipes, so that it flows back, even when we don't use any water inside the house. The house is located in front of a mountain with tank and field below a steep hill (see photos). The house was built in 1970s, mostly used as a vacation home, now we live here full time. It is a gravity fed system (that's what inspector told me), tank is baffle concrete tank, 1500 gallons. Previous owner passed away a few years ago, so I don't have any paperwork or plans of the set up. There are no visible problems, unless it rains really heavy, so basically 99% of the time, there are no wet spots or such on the field. Where would I start fixing this? As I understand, there are 2 major things that can be going wrong: 1. water flows can be coming down the mountain, saturating field and overflowing tank or 2. tank has a crack, and when there's a lot of water it comes in and overflows it back into the house. Just my guesses. As far as solutions, I understand that if tank has a crack, the whole tank is usually replaced. If it is the field that gets over saturated when it rains heavily, can that be fixed by not touching the actual field, but rather digging something like a french drain at the edge of mountain and field? If this is the case, how should this drain be constructed, the depth etc? I called a professional and they'll come up in a few days, but I'd like to have some ideas before hand. Thanks in advance for your input, it's VERY MUCH appreciated.