“There is no shortage of water in the desert but exactly the right amount, a perfect ratio of water to rock, water to sand, insuring that wide free open, generous spacing among plants and animals, homes and towns and cities, which makes the arid west so different from any other part of the nation. There is no lack of water here unless you try to establish a city where no city should be.” Edward Abbey
Sourcing and storing drinking water is a major limitation for vandwellers in general and boondockers in particular. Be ready to take advantage of water availability.
You may find it easy to ask for permission to collect some water from:
Be on the lookout for spigots, and watch for signs that the water may not be for human use.
Sourcing water from RV dump stations is possible but requires care; the water itself is likely potable but dump stations are prone to sewage splashing and other misuse by uninformed RVers. This means the spigots are likely contaminated.
Public sources of water will often be threaded to allow the connection of a potable water hose (like a garden hose but white in color) which can reduce manually carrying water back to the van. They can be found in the RV section of big box stores.
Note that even after you get permission the clerk may not have a key for spigots with no handle. Handles are often removed to prevent tampering (like kids turning on the spigot and leaving it on all night). Being able to say “I have a key!” may help speed up getting that permission – the clerk doesn't have to do anything.
A silcock tool fits spigots that have square shanks. The tools typically fit four different common sizes.
Note: carrying these tools may be an important survival tool.
Sinks and other non-threaded outlets can be tedious to extract water from. A water bandit is a rubber device that slips over an outlet and offers a male hose fitting on the other end.
Small or collapsible jugs may be easier to maneuver under sink faucets.
Water kiosks usually sell water for 25c/gallon. The way the stations are set up may require the use of a bucket or other tall container to collect the vended water.
Some RV service stations will sell water. The famous RV Pit Stop in Quartzsite has long fill hoses and sells R/O water for 25c/gal, but you can fill your tank with filtered well water for a flat $2.
Some small town water companies will have a public spigot priced (very cheaply) by the gallon.1)
Rainwater can be collected in clean containers unless near pollutants of some kind. Wind-driven debris is common in receptacles.
Indirect rainwater (suitable for non-potable uses) can be collected in large quantities off awnings and similar structures. Watch your van during rain to see where the water collects.
Water collected from open running sources should be assumed to be biogically suspect; see purification techniques .
Since water seeks lowest spots you might be able to see a source but not access it directly. A sierra cup or other receptacle can be strapped to a walking stick, bucket lowered on a rope, etc. Drill-powered pumps can help collect bucketfuls of water from shallow sources.
Water collected in puddles or ponds is the most likely to be contaminated with pathogens or to have concentrated pollutants. Use as a last resort and combine purification techniques (above).