simple flow measuring devices ...
Published by Christopher Brooks
simple flow measuring devices
Ruby - it depends somewhat on the flow and how your distribution system is set up, but a v-notch weir or parshall flume can be installed in an open channel distribution system and is the easiest and cheapest way to measure flow. There is a helpful guide to their use available here: http://waterrights.utah.gov/distinfo/measurement_devices.pdf
If you need to measure flow in an enclosed pipe there are a few methods that are simple and inexpensive, but require some knowledge of hydraulics to implement correctly. If you google the terms "flow measurement", "manometer", and "orifice plate" you should be able to come up with some resources to help guide you.
Good luck