Yes, our sensors can be retrofitted to existing leachfield trenches and beds. If the leachfield already has inspection ports (aka observation tubes) it is very easy. If there are no inspection ports, then these need to be retrofitted first. For plastic leaching chamber trenches (i.e. Infiltrator chambers) it is necessary to dig down to expose the top of the chamber, then drill a hole with a hole saw to insert the 2” (50mm) sensor sonar pipe with cap. For gravel (stone) trenches and beds, we have developed a special tool that makes it easy to retrofit 3” (75mm) inspection ports to these types of leachfields. For further details refer to our leachfield installation drawings and instructions under the Resources page.