Division of Labor and Industry


Keep Your Boiler Room Safe - Hot Water Heaters - Boiler and Pressure Vessel Safety - Safety Inspections


Keep Your Boiler Room Safe - Hot Water Heaters (Word document, download Word viewer for free)

Objective: To educate the public on the safe and proper use of Water Heaters.


Do Not---

  • Block ventilation openings to the water heater room.
  • Store flammables close the water heater.
  • Operate if it is overheated.
  • Operate without thermometer and Safety valve on.
  • Operate with expired inspection certificate.


  • Install a temperature and pressure safety relief valve, with relieving capacity equal to or greater than the heater heat input.
  • Provide a drain pipe from the safety valve directly to within 6 inches above the floor.
  • Install a thermometer on water discharge pipe.
  • Report to the Chief Boiler Inspector for the water heaters to be installed, at least 30 days prior to installation.
  • Keep your Water Heater Room clean.
  • Keep a check on leakages and rectify without delay.
  • Don't store flammables in the Heater Room.
  • Keep the Heater Room ventilated


  • Have the heater inspected externally biannually, as required by State Law.
  • Test safety devices on a periodic basis.
  • Inspect the water heater regularly for proper operation.
  • Maintain a log of maintenance, repairs and controls tests.

Be aware that if not cared for properly, a 20 gal Storage Water Heater, can explode with enough energy to rocket through a three story building, scald all those within, and cause structural collapse and fire.

A room containing a Water Heater should stay properly ventilated. Deadly Carbon Monoxide will be produced if the Burner does not have adequate air circulation in order to prevent incomplete fuel combustion.

Drain water from your tank two to four times a year. When water is heated, calcium carbonate settles to the bottom of the tank. This sediment reduces the efficiency of your water heater, as well as its storage capacity and eventually its lifespan.

A Storage Water Heater should be installed on a solid floor or on a structure designed to safely support a Water Heater completely filled with water. Clearance measurements must comply with all jurisdictional requirements.

A Water Heater is - -
a type of Hot Water Supply Boiler. They are exempt from the Maryland Boiler and Pressure Vessel Safety Act if NONE of the following limitations is exceeded.

  • Heat Input 200,000 BTU/Hr
  • Water Temp 210 Deg F
  • Nominal Water Cap 120 Gal

We are here for your protection.

For additional information, contact:
Division of Labor and Industry
Elevator and Escalator Safety

1100 N. Eutaw Street - Room 601
Baltimore, MD 21201
Fax: 410-333-7721
e-mail: dldlisafetyinspection-dllr@maryland.gov

Emergency telephone number: 410-767-2990