Doesn’t my washer empty out there? So detergent that didn’t pass through my body is OK?
I said “basically.” Liquid detergent is fine.
But that still doesn’t tell you the frequency of clean-outs. 3-5 years may be too high or too low depending on the situation.
Washing machines are hell on septic systems … consider a French drain for just that appliance …
There should be a distribution box a few feet downstream of your tank, it’ll be buried so you might have to dig around to find it … this takes the outflow of the septic tank and divides it up into the multiple drain lines that leech out in your field … if you think roots are clogging up your system, this is the best place to run an auger through the lines …
I want to thank everyone for their input to my questions. My tank was pumped and they said it needed it badly. I now have a clean tank and won’t have to pump again for a couple of years. My septic guy said that I had a lot of solids and that I should do Rid-x once a year IF its needed. Right now that won’t be necessary. I will have to have a tree removed and some bushes. Once again thank you guys so much. 
We don’t allow the washing machine water into the septic. It has it’s own drain lines that leach out. And we also have a pipe to put the gray water into the yard for irrigation.
I think most of what’s been written here is accurate. We’re every 4-5 years on a 1000 gallon tank. My septic guy wants me to do it annually, but after decades of living with septic, and everything I have read, I believe that’s just revenue enhancement for him.
We are vigilant about what we put down there, because we’d rather be safe than sorry.
We are also on a sandy hill, and I suspect we have optimal perc rates.