Expansion Tank Installation
Code Compliance · No Trip Charge
If your home has a closed plumbing system, an expansion tank is required by code - and skipping it can void your water heater warranty. We install them correctly the first time.
What's Included
- System pressure test - We verify your home has a closed system and measure water pressure before selecting the correct expansion tank size.
- Correct sizing and installation - Expansion tanks are sized based on system pressure and water heater tank volume. An undersized tank provides little protection. We select the right size and install it on the cold water supply line.
- Pre-charge verification - We verify the tank's air pre-charge matches your system pressure - a step that's often skipped and leads to premature tank failure.
When you need an expansion tank
- You have a pressure-reducing valve (PRV) on your main water line
- You have a backflow preventer installed
- A new water heater installation requires one by code
- Your existing expansion tank is waterlogged or failed
- T&P valve releases water periodically (a sign of thermal expansion)
- Water pressure fluctuates noticeably throughout the day
- A home inspection flagged the absence of an expansion tank
- Your water heater warranty requires one
Frequently Asked Questions
- What is an expansion tank and why do I need one?
- When water heats up, it expands. In an open plumbing system, that expanded water pushes back into the municipal supply. In a closed system (where a PRV or backflow preventer blocks that path), the expanded water has nowhere to go - which creates pressure spikes that stress your water heater, pipes and fixtures. An expansion tank absorbs that pressure.
- How do I know if my home has a closed plumbing system?
- If your home has a pressure-reducing valve on the main water line or a backflow preventer, you have a closed system. We check for this on every water heater installation.
- Can I skip the expansion tank to save money?
- We don't recommend it. In a closed system, skipping the expansion tank is a code violation in most jurisdictions, can void your water heater warranty and causes premature wear on the T&P valve - which is a safety device you don't want degraded.
- My T&P valve drips occasionally - is that related?
- Very likely yes. A T&P valve that periodically releases water is a classic sign of thermal expansion pressure in a closed system. An expansion tank typically resolves it.
- How long does an expansion tank last?
- 5–10 years in most cases. The internal bladder eventually fails, at which point the tank becomes waterlogged and stops functioning. We check expansion tank condition during maintenance visits.
Related Services
Call us at (770) 334-4738 or book online.