Yes, lots of people who do not have homes which are connected to city/county sewer collection systems have leach beds in their yards between their home and their septic tanks.<quoted text>
Sort of, leach really means more of a filtration. Nutrients being leached from the soil and so on.
The puzzling thing is that leach and leech doesn't really have any crossover in the definitions that would let you confuse them. I just assume he couldn't spell leech and got a bit embarrassed when called out, which is natural. Nobody likes being wrong.
It would be quite a frightening prospect to wake up and find a leech bed in your back yard, I would guess. All those creepy crawly bloodsucking parasites slithering around, just itchin to climb up your pantlegs.