What to Do When Your Boiler is Leaking – is it an Emergency?

A boiler on your commercial property can be damaged depending on how you maintain and use it. When a boiler starts leaking, it may indicate an issue that requires immediate attention.
But what steps do you take when your boiler starts leaking? Many people often wonder whether they should treat a leaking boiler as an emergency or not. In this guide, you will learn about how to fix a leaking boiler and whether you should treat it as an emergency.
Is a Leaking Boiler an Emergency?
Boiler leaking can be an emergency depending on the underlying issue and the severity of the problem. If the boiler has gas leaks, always consider it an emergency, and you should treat it as such. Through the remainder of this article, leak will mean a water leak.
Before moving forward, let’s clarify what we mean by “emergency”. The term emergency here means that the boiler is unsafe to operate and should be shut down immediately as there is potential risk to life and limb. This could be due to a leak in the boiler’s pressure vessel, or where a leak is impinging on electrical components. In any case, leaks should always be taken seriously, even if not an “emergency”, leaks should be corrected quickly to avoid further damage.
Small amounts of water leaking from the boiler may or may not be an emergency, depending on where the leak is originating, but over time the leak can damage other components and potentially make your boiler irreparable. It is imperative to repair your leaking boiler to prevent damage and costly repairs or replacements.
If your commercial boiler constantly leaks water, and you cannot positively identify the source as not the vessel itself (i.e. a fitting external to the boiler vessel), you should consider it a severe problem that requires emergency boiler repair, the boiler should be safely shut down and isolated until a diagnosis/repair can be made. If you do not understand the boiler components and functions, it may not be easy to determine why your boiler is leaking and how to repair it. In this case, you can hire an experienced technician to inspect and repair your boiler.
What to Do When Your Commercial Boiler Is Leaking Water

If you experience water dripping from the boiler or pipes, you should act quickly to fix the issue before it gets out of hand and causes more damage to your boiler. There are various things you can do to prevent your boiler from leaking. Below are steps to take before calling a service technician.
- Turn off your water supply to the boiler and/or piping in question
- If you have a backup boiler, bring it online
- Allow the boiler to cool
- Lock-out and tag-out electrical, water, and fuel supplies to the boiler (this can be handled by your boiler service company)
- Drain the system (this can be handled by your boiler service company)
- Dry off the water on the ground
- Identify the leaking component/fitting for reference by the technician
If you notice water leaking from your boiler, it’d be best to schedule help from a qualified boiler service company immediately. The boiler technician will inspect the boiler to determine the cause of the leak, and fix the issue.
Stop Boiler Feed System Overflow Leaks
Overflow leaking occurs when there is excess water in the feedwater tank or deaerator. These tanks are fitted with overflow fittings (and traps in the case of a deaerator). This could happen if there is a problem with the makeup water valve (whether a float type, or motorized valve), such as excessive supply water pressure or a hole in the float. This could also be caused by an undersized tank, or excessive condensate returns (potentially oversized return pumps), or plant operations at startup conditions (condensate is not returning quickly and the makeup system is adding water, then the condensate returns causing an overflow). Here are steps to stop the feedwater tank overflow from leaking.
- Identify the leaking water as coming from the tank’s overflow
- Check if the float valve is stuck down/not responding to tank level, or that the motorized valve is modulating
- Schedule to have a competent boiler service technician visit to complete the diagnosis
- As the overflow should already be piped to a drain, this is typically not an emergency, but losing condensate is expensive and should be corrected as quickly as possible.

Reasons Your Boiler is Leaking Water from Underneath
Water leaking under the boiler may indicate the leak is occurring on the boiler’s pressure vessel. This leak could also be caused by a fitting going into the vessel, or a leak with the vessel itself – such as leaking tubes in a scotch marine boiler. These types of leaks may run along the inside of the boiler cladding and drip out of the bottom.
If the leak is happening on the vessel itself (or within the ASME Power Piping, B31, boundary), the repair will likely need to be made by a repair company holding an ASME R-Stamp (unless the repair is simply tightening a loosened mechanical connection).
Leaks of this nature, where you can’t positively identify the leak as minor (coming from a fitting outside of the boiler pressure vessel boundary), should be treated as an emergency until the exact nature of the leak is diagnosed. You should do the following:
- Safely shut the boiler down
- Call a competent boiler service company to schedule service
- Allow the boiler to cool
- Lock-out and tag-out electrical, water, and fuel supplies to the boiler (this can be handled by your boiler service company)
- Drain the system (this can be handled by your boiler service company)
- Dry off the water on the ground
The boiler service company will make a diagnosis and help plan a course of action to repair your boiler.
Should my Leaking Boiler be Repaired or Replaced?
This question can only be answered after a thorough review of your current boiler system. The review should include the severity and location of the leak, the extent of the underlying damage that caused the leak and any resulting additional damage, boiler equipment age, current controls, how your boiler fits in with your current and future operation needs and much, much more.
Commercial Boiler Inspection and Maintenance
Knowing what to do when your boiler is leaking can help you avoid many issues that can cost you a lot of time and money in the long run. Consider regular boiler inspections and maintenance from an experienced engineer to identify and prevent potential issues. Need help from a boiler engineer? Contact us for a free consultation and all your questions concerning boiler operation or repair.
