As most folks who sail and live on board at anchor learn,  clear or white plastic of any sort, tends to break down due to UV degradation faster than dark colored plastic. This is definitely the case with the folding water jugs we like to use on board Taleisin. 
The folding jugs have a lot of advantages over hard plastic ones. Not only are they less damaging to the boat, they conform to the shape of our bilges so we can use them to carry extra water for longer passages and they can be folded up and stored away when they aren’t in use. Unfortunately the only ones readily available in most marine and camping stores are clear plastic. By good fortunate, we came across black colored plastic ones when we were in a camping supply store several years back. They are not sold as water jugs, but as solar showers.  They have slightly stronger handle connections than the clear water jugs, but are otherwise exactly the same.  When our normal camp store supplier ran out of stock, we decided to contact the Canadian Company, Reliance Plastic Industries, which makes these. They sent us to the web and now we can order Solar showers easily from www.target.com. If we make sure the jugs aren’t resting against any sharp corners or bolts when we store them full of water in the bilge we can use them for four or five years of voyaging before they need replacing – and remember we use them to carry the vast majority of the water we use, from shore to the boat.