Mercer County · Underground storage tank (UST) work — NJDEP-regulated
Much of Princeton's housing predates the region's 1970s–80s switch to natural gas, so abandoned underground oil tanks are common — frequently undocumented and only found by a sweep during a sale.
8 NJDEP-certified UST firms are based in Mercer County (statewide firms serve Princeton too):
Robbinsville Twp · Closure + HHO Subsurface Evaluation
Robbinsville Twp · Cathodic Protection Specialist + Closure
Trenton City · Closure + Subsurface Evaluation
Trenton City · Closure + Installation-Entire UST System
Robbinsville Twp · Closure + Subsurface Evaluation
Ewing Twp · Closure + Subsurface Evaluation
All Mercer County firms · full New Jersey list
Removing a buried residential heating-oil tank in New Jersey typically runs about $1,500–$3,000 when there's no leak. A leaking tank means soil remediation, which can push the total into five figures — which is why a pre-purchase sweep (~$200–$500) matters. A certified firm gives a firm quote after locating and assessing the tank.
Yes. Underground tank closure and removal in New Jersey is regulated by NJDEP and the local construction and fire officials — the work must be done by an NJDEP-certified firm, with permits pulled and the closure properly documented. That paperwork is what protects you and any future buyer.
8 NJDEP-certified UST firms are based in Mercer County, and statewide firms serve Princeton as well. New Jersey requires companies that test, close, or remove underground storage tanks to hold NJDEP certification by category — "subsurface evaluation" is the one most relevant to pre-purchase sweeps.
Tell us what you need — we'll connect you with state-certified companies serving your area. No obligation.