It looks like I'm late with my response (as usual I hear you murmer!)
Both my waste water container ( black polythene type..see below) and the polythene fresh water carrier stow neatly in the front locker of the caravan alongside the calor gas bottle, spare wheel, electric cable, the steady winding handle, nose weight gauge (please don't start on me!) and the caravan storm strap and awning pegs.
https://www.amazon.co.uk/Caravan-Waste-Container-Black-Litre/dp/B003V5EY26?SubscriptionId=AKIAILSHYYTFIVPWUY6Q&tag=duckduckgo-ffab-uk-21&linkCode=xm2&camp=2025&creative=165953&creativeASIN=B003V5EY26
I have no problem with maintaining a reasonable "noseweight" of a tad under 12 stone ( approx 75 kilogrammes) measured the " proper way!"
The fresh water and waste water containers weigh less than a pound each ( around half a kilo or so) but obviously quite a bit more when nearly full, I have a cheap fold up trolley for moving them when full and it's no problem even for a decrepit old codger like me.
The waste and fresh water container (and the cheap trolley) cost me around £12 for the lot as far as I can remember although I see they have gone up in price recently!
I know some folks will think that 4 gallons or so ( a tad less than 20 litres) is not a lot, and that clear polythene can encourage algae and the like, but we have never experienced any problems.
Ok (there are only the two of us (plus our dog) but it provides a good hot shower for myself and Mrs paws ( the dog, fortunately, is not too keen on showering in the morning !) and it does both of us with plenty of water left over for making the tea, washing up etc.
My caravan is quite elderly now about 22 or 23 years old and is equipped simply and inexpensively
(no expensive Aqua roll and Waste hogs for us!)
Just my two pennyworth,
and as always
Happy Caravanning
Regards to all
paws