I get where you’re coming from, but I’ve always wondered—does a dedicated line really make that much difference in places with newer plumbing? Most of my rentals are post-2000 builds, and I haven’t had too many complaints with the standard under-sink setup. That said, I’ve definitely had my share of late-night “why is the dishwasher bubbling over?” calls in the older units. Maybe it’s just a matter of how careful tenants are with what goes down the drain... or maybe I’m just tempting fate by not switching everything over. Anyone else notice a big difference between old and new construction on this?
Here’s what I’ve noticed after a few years of juggling both setups:
- Newer builds (post-2000) usually have better venting and smoother drain lines, so the standard under-sink hookup works fine most of the time. Less gunk buildup, fewer weird airlocks.
- Older places? That’s where I see the bubbling and backflow issues you mentioned. Grease and food bits just seem to collect faster, and tenants aren’t always careful about what goes down.
- Dedicated drain lines are definitely overkill in some newer units, but they’re a lifesaver in older ones where the plumbing’s seen better days.
- Cost-wise, retrofitting for a dedicated line isn’t cheap, so I only do it if I’m already opening up walls for something else.
- One thing I do in all units: install a high loop or air gap on the dishwasher drain. Cheap insurance against backups, and it’s code in a lot of places anyway.
Honestly, unless you’re seeing regular problems in your newer rentals, I’d probably leave them as-is. But yeah, tempting fate is always part of being a landlord...
