If your hot water heater is leaking, first work out where the water is coming from and whether it is still flowing. Water at a pipe connection, valve or drain fitting may be repairable; water emerging from the cylinder’s body can indicate corrosion and may mean the unit needs replacing. If the leak is steady, the source is unclear, or water is close to electrical equipment, act promptly and contact a plumber. Avoid touching wet switches or removing covers. A careful visual check can help you describe the fault, but repairs to pressurised, electrical or gas components are best left to a qualified professional.
Water can damage flooring, cupboards and nearby belongings even when the leak looks small. Start with safety, then limit the flow if you can do so without entering a wet area or handling unfamiliar controls.
Do not drain the cylinder or remove an access cover as a first response. Stored water can be hot, and the unit may remain pressurised or connected to electricity or gas. A plumber can determine what needs to be isolated and whether draining is necessary.
Water often runs down pipes or the outside of a cylinder before collecting at the bottom. A puddle beneath the unit does not, by itself, prove that the tank has failed. If the area is safe, look for the highest point that appears wet, and note whether water is dripping, spraying or flowing from a pipe. Do not reach behind the cylinder or touch a wet component to investigate.
| Where water appears | Possible explanation | What to do |
|---|---|---|
| Top connections or nearby pipework | A leaking joint, fitting or connected pipe; water may travel down the cylinder. | Keep the area clear and arrange a plumber if the leak continues. Do not tighten a fitting while the system is hot or pressurised. |
| Temperature and pressure relief valve outlet | The valve may be discharging, or a valve or system issue may need attention. | Keep clear of the hot outlet. Never cap or block it. Contact a plumber if discharge is steady, substantial or recurring. |
| Drain valve near the base | The valve may not be sealing properly or may be damaged. | Do not force the valve or attempt to remove it. Have it assessed, especially if water continues to flow. |
| Element cover or flange area on an electric cylinder | A seal or connection may be leaking; water can also travel from above. | Do not remove the cover. Keep away from wet electrical parts and call a plumber or appropriate service professional. |
| Cylinder seam, outer casing or base | The cylinder itself may be corroded or leaking. | Arrange prompt professional assessment. A leak from the tank body often points towards replacement rather than a simple fitting repair. |
| Floor nearby, but no clear wet point on the cylinder | A nearby pipe or appliance may be leaking, or moisture may be collecting on a cool surface. | Dry the area only if safe, then observe whether water returns. If the source remains unclear, ask a plumber to trace it. |
The table provides clues, not a diagnosis. A small leak at the top can look like a tank leak once water reaches the floor, while water coming from the cylinder’s shell may be difficult to distinguish from a nearby pipe leak. A plumber can inspect the source without relying on the puddle alone.
A temperature and pressure relief valve, often shortened to TPR valve, is a safety component. It releases water through a discharge pipe if conditions require it. The outlet may lead to a drain or terminate elsewhere, so the water may not appear beside the cylinder itself. Do not touch the outlet to check its temperature, and never cap, plug or obstruct the pipe.
A continuing or repeated flow should be checked rather than dismissed as normal. The cause may involve the valve or the conditions in the hot-water system, and a plumber can identify what is happening. Do not try to repair or adjust the valve yourself.
Water at the bottom can come from a connection higher up, a drain fitting, a component seal or the cylinder itself. If you can see water emerging through a seam or from the body of the tank, treat it as a potentially serious leak and seek professional advice promptly. Corrosion or failure of the cylinder shell is generally not a straightforward fitting repair; replacement may be needed after inspection.
If the casing looks dry but the floor keeps getting wet, check only what is visible and safely reachable. Nearby pipework, a valve discharge line or another appliance may be the actual source. Avoid pulling the cylinder away from a wall or dismantling any part to get a better view.
The repair decision depends on which component is leaking, the condition of the cylinder and whether the problem can be safely corrected. A faulty connection, valve or seal may be repairable, while a leaking tank body can make replacement the more practical option. Do not commit to replacing a whole unit based on a puddle alone; ask the plumber to identify the source and explain the options.
| Finding | Repair may make sense when | Replacement may be considered when | What to confirm |
|---|---|---|---|
| Pipe joint or fitting leak | The leak is limited to a connection and the cylinder itself is sound. | There is separate evidence of cylinder deterioration or other significant faults. | Ask which joint is leaking and whether the repair addresses the source rather than just the visible water. |
| Valve or drain fitting leak | The faulty component can be serviced or replaced and the rest of the system is in suitable condition. | The cylinder has additional damage or replacement is otherwise recommended after inspection. | Ask whether the valve is the source and whether its discharge pipe remains unobstructed. |
| Element seal or related leak | A serviceable seal or component is responsible and the cylinder is otherwise sound. | The leak has damaged the cylinder or other faults make a repair unsuitable. | Ask what part has failed and whether the unit needs to be isolated while the repair is arranged. |
| Leak through the tank body | A plumber confirms the apparent shell leak is actually coming from a repairable nearby component. | The cylinder shell is corroded or leaking. | Ask for confirmation of the leak location and a clear explanation of repair versus replacement. |
For an older unit, its age can be one factor in the decision, but it is not enough on its own to establish that replacement is necessary. If you know when the cylinder was installed, share that information with the plumber. Also consider the unit’s visible condition, previous repairs and the likely scope of the proposed work. A repair may cost less now, but it is worth understanding whether other faults are likely to require attention soon.
If replacement is recommended, ask what happens to the existing water and energy connections, whether the work includes removing the old unit, and what preparation or access is needed. The appropriate replacement depends on the home and its existing system, so avoid choosing a model based only on appearance or a general online recommendation. Ask the plumber to explain any changes required to the connections or installation.
Urgency depends on the amount of water, how quickly it is escaping, where it is going and whether there is an electrical or gas hazard. A minor drip caught in a safe container is different from water running across a floor or entering a wall or ceiling. Even a slow leak deserves attention because it can worsen or cause damage over time.
If you cannot safely shut off the supply, tell the plumber when you call. Do not delay seeking help just to take photographs or find the cylinder’s paperwork. If the area is dry and safe, a photograph of the visible leak and the cylinder’s label may help the plumber prepare, but neither is worth approaching a hazard.
A concise description helps the plumber understand the problem and its urgency. You do not need to diagnose it yourself. Share observations rather than guesses, and mention any steps already taken.
Ask the plumber to show you where the leak originates, explain whether the cylinder is sound, and outline the repair and replacement options before work begins. If replacement is proposed, ask what makes repair unsuitable and what the quoted work includes. This keeps the decision tied to the actual fault rather than the location of the puddle.
It depends on the leak and the equipment, so do not assume it is safe to keep using. If water is near electrical parts, the cylinder body is leaking, or the source is unclear, keep away and contact a plumber. Follow their advice about whether the water and energy supplies should remain isolated.
If a clearly identified isolation valve is dry, safely accessible and operates without force, shutting it may limit further water loss. If you cannot identify or safely reach it, do not experiment; contact a plumber or use the main shut-off only if you can do so safely.
The TPR valve releases water under certain system conditions, but continuous or recurring discharge should be assessed. The cause may be the valve or another issue affecting the system. Keep clear of potentially hot water and never block the outlet.
No. Leaks at pipe connections, valves or serviceable components may be repairable. A leak from the cylinder shell is more concerning and may mean replacement, but a plumber should confirm the source before you decide.
Do not apply sealant, tape or a clamp to the cylinder or a pressurised component. A patch may not control the leak and can complicate proper repair. Limit access to the affected area, shut off the water only if safe, and arrange professional assessment.
When a hot water heater is leaking, identify the visible source without touching wet, hot or pressurised parts. A fitting or serviceable component may be repairable; water from the cylinder body calls for prompt assessment and may mean replacement. If the leak is steady, the source is uncertain or there is any electrical or gas concern, keep clear and contact a plumber rather than attempting a repair yourself.
