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Our caravan has been sitting there for a while, so I got wondering what can I use to clean my caravan water tank?

The answer really surprised me, here’s what I found: Bleach (diluted at 12.5 ml per 100 L) is recommended as it’s the most effective and cheapest. You can use Milton Solution if you’ve already got it (it’s just diluted bleach that’s way more expensive). Commercially available caravan tank cleaning products are your next best option. White vinegar doesn’t kill dangerous bacteria like staph, while bicarbonate soda doesn’t kill most bacteria at all.


I was too! Here’s some of the details:

1. Household bleach: The best option to clean your caravan tanks

Think bleach is a dangerous chemical that should go nowhere water? I did.

But the truth? Not at all.

In fact: this is what’s recommended by the authorities to disinfect water tanks.

The Department of Health recommends you use 125 mL per 1,000 L of water to disinfect tanks, and the Department of Health and Human Services (Vic) recommends exactly the same thing.

Bleach is both cheap and highly effective as a disinfectant. It kills off bacteria like staphylococcus, streptococcus, E. coli and salmonella. It also kills the flu and common cold viruses.

Bleach is the best thing to clean caravan water tank

A reminder though: check the label of the product to make sure there’s no detergents, perfumes or fragrances added to the bleach…

Lemon-scented may smell fresh, but it’s not very good for you!

Cost to clean 180 L of tanks: About $0.05

2. Milton Solution: what’s the difference between Milton and bleach for cleaning caravan tanks?

Here’s something I learned while I was researching this: Milton Fluid is just diluted bleach!

Milton Anti-Bacterial Solution Has The Same Ingredient As Bleach

Normal household bleach is usually a 4-5% solution of sodium hypochlorite… Milton Antibacterial Solution is 2% of the same stuff.

When I checked today at Woolworths, Milton works out to be about $13.80 per litre. Bleach on the other hand is $0.60 per litre.

This means you’re paying around 46 times more for exactly the same thing!

Now, you might read that Milton is recommended over other bleach formulations because it doesn’t contain colouring agents or perfumes…

…that’s why you just buy the plain, unscented bleach

Cost to clean 180 L of tanks: About $2.50

3. Commercial caravan tank cleen products: Any good?

Yes, they’re just more expensive. Products like Tank Clean have been shown to be very effective at cleaning caravan water tanks. But one tub will be completely used to clean your tanks, and it’ll cost you about $15. Compare that to bleach which works out out to be about $0.05 to do the same job.

Caravan Tank Clean - Effective but Expensive

Cost to clean 180 L of tanks: About $15.00

4. White vinegar: Only good to clean caravan water tanks if you have no other option

After researching this topic the only time I could recommend white vinegar is:

  1. If it’s an emergency,
  2. there’s no other option, and
  3. You’re about do die of dehydration.

Why? Because it doesn’t kill everything.

An effective disinfectant (like bleach) kills 99.9% of germs. White vinegar?

White vinegar only kills about 80% of germs, and doesn’t kill dangerous bacteria like staphylococcus.

That being said: white vinegar (acetic acid) has been shown to kill things like salmonella, E. coli, and cold/flu viruses.

White vinegar is only good for cleaning caravan water tanks in an emergency

So even though it’s not as effective, it can still be a useful disinfectant if that’s all you’ve got. But if you have an option, bleach is the go. You’d hate it to be the one time there’s something nasty in the water. It’d be dangerous of me to recommend it otherwise.

Cost to clean 180 L of tanks: Vinegar does not properly clean your tanks.

5. Can you use baking soda to clean your caravan tanks?

Baking soda doesn’t kill most bacteria, including salmonella, E. coli. and staphylococcus. It might deodorise your tank… but that’s about it.

Bi Carb Baking Soda - No Good to Clean Caravan Water Tanks

What about the reaction between baking soda and vinegar?

I found this interesting:

Mixing baking soda and vinegar together is LESS effective than if you just put the vinegar in by itself

Why? Because when you react the two together, after the bubbles are gone you’re pretty much just left with diluted salt water.

The turbulence can help to unclog drains and it looks cool for making a volcano for a science experiment… but that’s about it.


If you’re asking what can I use to clean my caravan water tanks, then for 180 L worth you’re looking at:

  1. Household bleach ($0.05)
  2. Milton solution ($2.50)
  3. Caravan tank clean products ($15.00)
  4. White vinegar (doesn’t kill dangerous bacteria)
  5. Bicarb soda (doesn’t kill most bacteria)

Got your bleach?

Then check outHow To Clean a Caravan, Camper or RV Water Tank [Step By Step]

Comment below: anything surprise you here?