I'm thinking that repairing the plumbing leaks and getting the soil dried out could be a permanent solution.   

An addition of soil, a swale, or a French drain may be necessary.● Part of the patio on the east side of the garage has a negative slope.

They’re built for heavy use and have faster drying times—usually 30–45 minutes—without needing major electrical changes.If you’re up for a bigger investment, adding extra stackable units in the garage could be a great long-term fix, though it’ll mean some electrical work and setting up proper ventilation.I’d probably go for the commercial upgrade in your current space first—it’s quicker and might solve the bottleneck right away.

Clay soils mean that drainage is really important to prevent foundation issues.

I have a new-construction SFR property under contract, and the seller disclosed that there had been heavy metal contamination in the soil due to mining activity many years ago.

Flatter tends to be better, but even then you need to make sure the soil is stable to support your structures.  

It will be a little trying for 6 units to use - they're slower because they do both washing & drying - but that would be way better than expecting tenants to drag wet laundry around.

The auctions are just as dry as the MLS and wholesaler deals. 

Root intrusion is rare with plastic pipe because that means a crack that's going to admit soil as well and eventually bust completely, so if you have roots in PVC you might as well plan to excavate.

The process is very involved as you'll have to navigate pre-construction activities that involve architectural plans and approval from the city and then the construction activities (Shovel to soil) take anywhere from 5-9 months depending on how much your building.