On the Mark Plumbing, Heating & Cooling is a family-owned plumbing and HVAC company based in Marshfield, serving Boston's South Shore since 2018. The company handles residential and light-commercial plumbing, heating and air-conditioning work along the Route 3 corridor from Quincy to Plymouth, and states it covers Braintree, Cohasset, Duxbury, Hanover, Hingham, Hull, Kingston, Marshfield, Milton, Norwell, Pembroke, Plymouth, Quincy, Rockland and Scituate.
Homeowners who hired the company consistently describe fast, same-day or within-the-hour response for no-heat calls, burst pipes and after-hours emergencies, and several say they have called the company back for repeat work across different homes. Recent reviews describe a full furnace, central air conditioning and hot water tank replacement, a tankless water heater paired with a whole-house filtration system, and a well pump swap with a new water filter system. In a 2025 review, one homeowner said the company was the only contractor able to properly repair their Rinnai heating system after several others had failed, and that the technician corrected earlier contractors' work.
The company carries an active Massachusetts plumbing license (#4376-PL-C), verified with the state registry. It holds a 5.0-star rating on Google from 32 ratings and matching 5.0-star ratings on Angi and HomeAdvisor from three reviews each, plus a Better Business Bureau grade of A-, and Massachusetts building-permit records show 13 plumbing, gas and HVAC permits pulled across the South Shore over the past three years.
One thing worth confirming before booking: the company's own website advertises round-the-clock emergency service, while a HomeAdvisor profile for the business states it does not offer emergency services — worth a quick call to clarify current after-hours coverage.
For South Shore homeowners with plumbing or HVAC needs, from a failed water heater to a full heating-system overhaul, this is a family-run outfit with a long, consistently positive local track record and a verified state license, best paired with a direct check on current emergency availability and scheduling.
