Caravan water tanks that aren’t cleaned properly before or after storage can develop algae, bacteria, bad smells, and sediment buildup — even if the water looked clean when you parked up.
The problem is most tank contamination happens while the caravan isn’t being used, especially during warm weather or long storage periods.
This guide walks you through how and when to clean your caravan water tanks, using a safe, repeatable process that protects your plumbing system and keeps your water fresh.
What You’ll Learn
- Why caravan water tanks need cleaning before and after storage
- How to safely drain and flush tanks
- How to sanitise tanks without damaging seals or pumps
- Common mistakes that cause bad smells and blocked taps
- How often you should clean caravan water tanks
This guide is suitable for all caravan owners, including beginners.
When You Should Clean Caravan Water Tanks
You should clean your tanks:
- Before long-term storage (to prevent growth while idle)
- After storage (before using the water again)
- After buying a used caravan
- After contamination (dirty fill source, algae smell, debris)
- If water smells, tastes odd, or discolours quickly
Skipping tank cleaning is one of the most common causes of plumbing issues later on.
Step-by-Step: How to Clean Caravan Water Tanks
1. Fully Drain All Water Tanks
Start with empty tanks.
- Turn off the water pump
- Open all tank drain points
- Open taps to allow air in
- Let tanks drain completely
This removes stagnant water and loose sediment before cleaning begins.
2. Flush the System with Fresh Water
Once drained:
- Refill tanks with clean potable water
- Run all taps (hot and cold)
- Flush until water runs clear
This step removes loose debris and prepares the system for sanitising.
3. Sanitise the Water Tanks
Use a caravan-safe sanitising method (not household bleach at full strength).
General process:
- Add diluted sanitising solution to tanks
- Fill tanks completely
- Run taps until solution reaches all lines
- Leave to sit for recommended time
This kills bacteria, algae, and biofilm inside tanks and hoses.
4. Flush Out the Sanitising Solution
After sanitising:
- Drain tanks fully again
- Refill with clean water
- Run all taps until no chemical smell remains
Never leave sanitising solution in the system during storage or use.
5. Clean Filters, Strainers, and Tap Aerators
After tank cleaning, sediment often collects downstream.
Check and clean:
- Pump inlet strainer
- Inline water filters
- Tap aerators
This prevents reduced flow and blocked taps after cleaning.
Cleaning Caravan Water Tanks Before Storage
Before storing your caravan:
- Clean and sanitise tanks
- Drain tanks completely
- Leave taps open
- Turn off the water pump
Dry systems reduce algae growth and prevent smells.
Some owners choose to store tanks empty, others full with treated water — always follow manufacturer recommendations.
Cleaning Caravan Water Tanks After Storage
After storage:
- Inspect tanks and fittings
- Flush tanks before use
- Sanitise if water smells or looks cloudy
- Clean filters before first trip
Never assume stored water is safe without checking.
Common Mistakes to Avoid
- Using undiluted household bleach
- Forgetting hot water system lines
- Leaving chemical solution in tanks
- Ignoring filters and aerators
- Only cleaning “when it smells bad”
Most water issues start with poor tank hygiene.
How Often Should You Clean Caravan Water Tanks?
Recommended frequency:
- Every 6–12 months (regular use)
- Before and after long storage
- Immediately after contamination
- After buying a used caravan
More frequent cleaning is better than reactive repairs.
Key Takeaways
- Storage is when most contamination occurs
- Draining alone isn’t enough
- Sanitising kills hidden bacteria and algae
- Filters clog after tank cleaning
- Clean tanks protect pumps, taps, and health
Next Steps
If you’re experiencing bad smells:
👉 Why Caravan Water Smells and How to Fix It
If taps are blocked after cleaning:
👉 No Water Coming Through Caravan Taps? Troubleshooting Guide
For a full system service:
