Install a brass drain valve at each low spot of the feed line. Thread the valve into the tee with Teflon tape.. To tunnel under walkways, attach a pointed sluice nozzle to a length of PVC pipe.

Just duct-tape some PVC pipe to your vacuum's hose and you're all set. DIY Life has the details: To clean cobwebs off of the ceiling all you need is some duct tape and some PVC pipe!

Working with PVC pipe in tight spaces and around plumbing structures can be difficult. If you just need to make a simple bend, you can do so without using elbows or fittings.