There are a number of plumbing problems that can be considered severe and cause significant damage if not addressed promptly. Some examples include:

Burst pipes: This can happen due to a number of reasons such as freezing temperatures, corrosion, or damage. Burst pipes can cause significant water damage to a home or building, and can also lead to mold growth if not addressed quickly.

Sewer line blockages: This can happen due to a buildup of grease, debris, or tree roots. A blocked sewer line can cause raw sewage to back up into the home or building, causing significant health hazards and damage.

Gas leaks: A gas leak can be caused by damage to a gas pipe or a malfunctioning gas appliance. Gas leaks can be extremely dangerous and can lead to fires or explosions if not addressed immediately.

Leaking or malfunctioning water heater: A leaking water heater can cause significant water damage and can also increase the risk of electrical shock if the water comes into contact with electrical wiring. A malfunctioning water heater can also cause hot water shortages.

Foundation cracks: If the foundation of a building is damaged, it can cause structural problems, leaks and mold growth, which can require costly repairs.

Sump pump failure: If the sump pump fails, it can cause basement flooding, especially if there is heavy rainfall.

These are just a few examples of the worst plumbing problems, but there are many others that can cause significant damage and be costly to repair. It’s important to maintain regular inspections and take care of small problems before they become big ones.