This is not an easy explanation, but here I go. Yes, top load washers are generally water wasters and too much water does hurt your septic system. Here’s how. Imagine you do 3 loads of laundry in one day. (A) That washer takes 10 gallons to fill up and 4 cycles to complete one load, that’s 40 gallons of water per load.
Now multiply that by 3 loads and you have 120 gallons of fresh soapy water. I also need to add that a septic tank is a disgusting, germ ridden place and now add 120 gallons of fresh water. All those germs and bacteria just got pushed out of your septic tank. Now the septic tank needs to “take over” that fresh water. It’s a case of one step forward, take two steps back. It takes time to recover this load. (B) Now your typical front load washer uses about 6 gallons of water. For it’s compete cycle. Times that by the three loads and you have 18 gallons of water for you system to process. Much easier on the entire system.