drainage responsibility

We've received our place built by Clarendon Homes. As part of the plan we requested that they install hot and cold water pipes and drainage so we can engage our own contractor to install the butler pantry. We've had problems with the drain since moving in and found out through a licensed plumber that the drainage is not connected to any sewage pipe. Instead it is just buried under ground, so we've been pumping water into the grass for the last 2 years. Reached out to Clarendon and they said it is our/contractor's responsibility, does that sound right to you?

Hi YingZhou
I suggest you get a copy of the plumbing diagrams from your local water authority and see what was submitted by the builder and then post back. OT, Quite often "provisions for future plumbing by owners contractor" could mean anything..check your contract specifications Drawings, etc.

From what you posted you have paid for capped service provisions for future use, that would require complete hook up to sewerage.
It seems builder missed it and now does not want to know about it.
What state are you in?