In the US I have a first need pump, but given most outings are only 1 week max here, a 26L water container lasts just fine. There's always a flat of bottled water in the back of our 80 so that's another 12L or thereabouts if needed.
In camp most water usage is cleaning things up versus cooking/drinking etc. We are generally quite frugal since I have instilled in my kids water conservation due to my oz camping background.
In oz where the trips are longer and water sources are very scarce in the inland desert areas, I take more water and have a filter for the occasions where we do find water. In some places the water is VERY putrid and I can't even imagine attempting to use a filter. Here's a particular bad water hole with dead emus in it (eek):
For years I'd used a Pur pump though producing enough water for a group became somewhat tedious even with shifts of people pumping. Just takes too long.
A few years ago I tried a Sawyer gravity filter (I purchased just the element):
The Sawyer has proven to be a great product (at least for vehicle based use). Here's a picture of it in use. I just made up some hose connections to interface the Sawyer to a charcoal filter (improves taste and also acts as a prefilter) and used with a solar shower bag. More info ->
http://www.george4wd.taskled.com/h2ofilter.html. Water transfers directly to plastic water containers in the vehicle:
On my last trip I went to a custom water bladder (about 70L) that sits under a wood 'box' on the cargo floor of the vehicle. That keeps weight low and I have hoses to go in/out of the bladder and taps on both. I can now just use gravity to take water out of the bladder via the outlet hose - too easy
I've also used a small pump to push water through the two filters to take water directly from clean waterholes etc - speeds things up considerably.
Here's an example of using a Whale submersible pump to get water from a covered gnamma hole (nearly 10000L in this one, it's a beauty). We're filling buckets up (obviously not filtered) so we can have some nice showers once we've set up camp:
Anyhow this is what works for my vehicle based camping use.
cheers,
george.