If you have hard water the treatment is an ion exchange water softener... no ifs, ands, or buts,

NO FILTER removes hardness.

Along with removing hardness a softener will lengthen the service life of your plumbing, fixtures, appliances, clothes, save you a bunch on soap and detergents and make your hair silky smooth.

There is NO evidence that ion exchange softeners harm septic systems and you can research that using Google until your eyes bleed from reading.

Some locations prohibit running the softener effluent (drain water during regeneration) into a septic system but allow running it to a french drain.

A properly sized and correctly set up softener will use about 50 gallons of water or so on a weekly basis for regeneration for an average family and not too nasty water conditions. you definately want a contemporary softener that regenerates on demand as required.

Softeners do not add salt to the service water. They add sodium (if you use sodium chloride as a regenerant) or potassium (if you use potassium chloride as a regenerant) to the service water. The chlorides go to drain during regeneration and that goes to the septic or other drain.

As an example... we've been on our septic system for 15+ years. My water is 26 to 30 grains hard (that is ludicrous hard) and with a family of two and the softener regenerating every 8 days at maximum our septic system functions perfectly and gets pumped every 5 years. When the septic guy comes to pump he remarks that I could have waited another 5 years easy.

Thank you for your response! My main concern is the laterals. Most of what I've read say the septic itself should be fine, but the drain field could have problems. Since it already does, I hesitate to do anything "iffy".

We'll call our septic company and get their 2-cents.

I've also read that the discharge can go to a greywater system or even on the ground. We could discharge it to our gravel driveway, or do a greywater pit.

In general, septic people know alarmingly little about water treatment and that is a shame.

If you are having drain field problems then you have big fish to fry and a softener or not is small potatoes. According to everyhing I've read and my own experience a softener has little to no effect on a properly operating septic system. There are those I've read that disagree but so far haven't come up with any thing in the way of substantive data to prove their position.

You can just dig a french drain separate from the septic.