If you want to know how to install a water heater in Hanahan, SC, the honest answer has two halves. The sequence is simple to describe: shut off, drain, remove, set, connect, fill, test. The risk lives in the details, and the details are gas connections, exhaust venting, 240 volt wiring and the relief valve.
LLR's plumber page says residential plumbing work over $500 requires a license. We cannot tell you how that applies to a homeowner working on their own house, so ask South Carolina LLR and the City of Hanahan Building and Codes department before you buy a tank. This guide shows each task so you can decide which ones you would do.
DIY or hire: a job by job table
Treat the last column as a starting point, and check your local rules before you pick up a wrench.
| Task | What can go wrong | DIY or hire |
|---|---|---|
| Draining and removing the old tank | Scalding water, a heavy awkward lift, a flooded floor | DIY with a helper, if you shut off power and fuel first |
| Setting a drain pan and the new tank | An unlevel tank, no safe path for a leak | DIY |
| Water connections with flex connectors and shutoff valves | Slow drips at fittings, wrong hot and cold sides | DIY if you can sweat or use push fittings well, otherwise hire |
| Gas connection and leak test | Gas leak, fire, explosion | Hire |
| Exhaust vent and draft | Carbon monoxide entering the home | Hire |
| 240 volt circuit, breaker and elements | Shock, fire, a dry fired element | Hire a licensed professional for the wiring |
| Relief valve and discharge line | A plugged or mis-sized valve that cannot do its job | Hire unless you can read and follow the manual exactly |
| Expansion tank | Pressure spikes, a relief valve that drips every cycle | Hire if you are unsure of your system pressure |
| Permit and inspection | Work that fails a later inspection or holds up a home sale | Ask the city before you start |
For gas models or any unit that needs venting, hiring a licensed plumber is the safer path.
Home installs still fall under the plumbing code. The City of Hanahan lists the 2021 International Plumbing Code (IPC) and the 2020 National Electrical Code (NEC), each with South Carolina modifications, which cover the relief valve, venting and the electrical supply.
Before you start, ask the City of Hanahan Building and Codes department whether the job needs a permit and an inspection.
Sources: City of Hanahan, Building Codes and SC LLR, Building Codes in Effect for South Carolina. Checked October 2026.
Which parts of the job a careful homeowner can do
Removing the old heater is hard work more than skilled work. You close the cold supply valve, turn off the gas valve or the breaker, attach a hose to the drain valve, open a hot faucet upstairs to let air in, and let it empty. The water at the bottom of a tank can still be hot, so route the hose carefully.
Setting the new unit in a pan, leveling it and making up the water connections is the second manageable block. Hot and cold are marked on the new tank, and the shutoff valves and flexible connectors should be new. If you can make a leak free connection on a sink supply, you can make one here.
The line gets drawn at gas and exhaust. Homeowners in Goose Creek and Ladson can call us when the vent or gas connection looks wrong.
The installation sequence a plumber follows
This is the order of work for a standard tank swap.
- 1
Shut off fuel, power and water
Turn off the gas valve or the breaker, then close the cold supply to the heater. Open a hot faucet in the house so air can enter.
- 2
Drain and disconnect
Drain the tank to a floor drain or outdoors, then disconnect the water lines, the relief valve line, and the gas or electrical connection.
- 3
Set the new heater
Place it in a pan, check that it is level, and confirm clearances in the manual for the vent, the door and the combustion air.
- 4
Make the water and safety connections
Connect cold and hot with new shutoffs, install the relief valve and its discharge line, and add an expansion tank if the system needs one.
- 5
Connect gas and vent, or wire the circuit
Gas needs a leak tested connection and a vent that draws properly. Electric needs the correct breaker and wire size.
- 6
Fill, purge and test
Open the cold supply and run a hot faucet until air stops spitting out. Only then restore power or light the burner, and check for drips, vent draw and relief valve operation.
Ready to book?Call and we will find the earliest slot, often the same day when the schedule allows.
Call (855) 575-2890Gas, venting and carbon monoxide
A gas water heater burns fuel in a sealed chamber and sends the exhaust up a vent. If the vent cracks, separates or draws poorly, exhaust gas enters the house. A federal Consumer Product Safety Commission recall notice for one tankless model describes the hazard directly: the exhaust duct can crack and let gases escape inside the home, which creates a carbon monoxide poisoning risk.
That is why vent work belongs to a licensed plumber. It is also why every home with a gas appliance should have working carbon monoxide alarms. After any install, test the alarms, and if one sounds, get everyone outside before you call a water heater installer or 911.
The relief valve and expansion tank are not optional extras
One major manufacturer's manual says not to plug the temperature and pressure relief valve opening, warning that doing so can cause property damage, serious injury or death. It also warns to keep people clear of the discharge outlet. The discharge line should be sized and routed as the manual and local code direct.
Many local codes require backflow preventers, which close the system. The same manufacturer's expansion tank manual says a closed system requires an expansion tank, and without one the relief valve will discharge on every heating cycle. If your relief valve drips after each heating cycle, call a plumber to test the pressure.
Permit, license and paperwork checks before you start
Do these before you buy a tank or hire anyone.
- Ask the City of Hanahan Building and Codes department whether your swap needs a permit and an inspection
- Read the new heater's manual for clearances, vent type and relief valve piping
- Verify any plumber you hire with South Carolina LLR, which licenses the individual
- Ask contractors for their Certificate of Authorization if a company is doing the work
- Write down the model, serial number and date code of the old and new heaters
- Confirm what the manufacturer's warranty requires from the installer
The Department of Energy also advises checking with your city about permits and local codes before installing a water heater yourself.
When an install problem becomes an emergency
A new heater that leaks at a connection can be fixed in daylight if you close the supply valve. Stop and call for help if you smell gas, if a carbon monoxide alarm sounds, if the relief valve is spraying steam or hot water, or if the tank is dripping near wiring.
Leave the building for gas or alarms and call 911. For the water side, close the cold valve and call (855) 575-2890 for emergency water heater repair.
Hanahan local note: Dominion Energy, LLR licensing and the permit question
The City of Hanahan Public Works page lists Dominion Energy for electric and natural gas service. If you smell gas, go outside, call 911, and then call Dominion Energy from outside the building. If you are moving to a larger gas appliance, ask Dominion Energy whether your meter and service line suit the added load.
The SC Residential Builders Commission, part of the Department of Labor, Licensing and Regulation, licenses residential plumbing contractors. LLR licenses the individual, and a Certificate of Authorization is the company license. Use LLR's licensee lookup to confirm any plumber before they touch your gas or water lines, and do not rely on a business card or a truck door.
Ask the City of Hanahan Building and Codes department about permits and inspections before you begin. We do not state permit rules from memory, because they can change and may depend on the fuel and the scope of work. If the city says a permit is needed, ask who will pull it and who schedules the inspection.
- Sources checked (city government page (City of Hanahan Public Works), state licensing agency (SC LLR Residential Builders Commission), federal safety agency (U.S. Consumer Product Safety Commission recall notice), manufacturer installation manual (A. O. Smith), federal energy agency (U.S. Department of Energy))
- SC LLR, Residential Plumber License
- SC LLR Licensee Lookup (linked from LLR plumber page)
- U.S. CPSC, Gas Water Heaters recall page
- A. O. Smith, Thermal Expansion Tank manual
- U.S. Department of Energy, Tankless or Demand-Type Water Heaters
Frequently asked questions
Can I install a gas water heater myself?
We recommend a licensed plumber. Gas connections and exhaust venting are where errors cause fires and carbon monoxide exposure. Check with LLR and the City of Hanahan Building and Codes department about what applies to your own home.
Does a water heater replacement need a permit in Hanahan?
Ask the City of Hanahan Building and Codes department. Rules can depend on the scope of work, and we do not state them from memory. If a permit is required, find out who pulls it and when inspections happen.
How do I check that a plumber is licensed in South Carolina?
Search the individual on LLR's licensee lookup, which is linked from the Residential Plumber License page. LLR licenses the person, and a Certificate of Authorization is the company's license, so ask for both when a company does the work.
Do I need an expansion tank with a new water heater?
If your system is closed by a backflow preventer, check valve or pressure reducing valve, the manufacturer's manual we reviewed says an expansion tank is required. A plumber can test your static pressure and tell you.
Who do I call if I smell gas in Hanahan?
Leave the building, call 911, and call Dominion Energy from outside. The City of Hanahan Public Works page lists Dominion Energy for natural gas. Do not use switches, lighters or your phone inside the building.