Mom's house has a septic system with a "drainfield". which with five people in the house would often be saturated. We didn't have the $ to put in new (plus by then you had to put in a "turkey mound" - butt ugly hill type thing in the middle of your yard)
The washer hose, where the water empties out, is just slung into the drain pipe. I've never lived anywhere that it was hard plumbed. dad rigged a second drain from the utility sink, through the garge wall, to a hose spigot. Mom just drained the water out the end of the driveway so it'd run into the gully and down the hill, soaking into the ground there instead of into our drainfield. dad had an on/off valve on the spigot too, so that you could back up the wash water into the sink. which we'd do if we had to use the laundry room toilet, (scoop a bucket of water out of the sink) or if mom had something nasty greasy to soak, or to soak the bbq grills. If she soaked something gross, she'd let the water out through the regular drain to go through the septic.
it would have been pretty easy to have that hose drain into a rainbarrell, right in the garage even would have worked. sometimes we'd wash a car with the laundry water. but usually it just went into the woods. (bleach loads went down the regular drainpipe. and she always used biodegradable, non sudsing detergent.)