It’s a cheesy fantasy flick. There is a townlike area, with two rival factions. There is only one water source in the town, which one faction controls. The hero (who is buddies with a religious dude in the town) hires himself to one of the factions as a mercenary, but is actually trying to undermine the whole thing.
Could it be that movie ?
Did it star David Carradine? I can think of at least three movies that had that same basic plot, including (I think) at least one Clint Eastwood western…
You’re probably referring to the 1984 film The Warrior and the Sorceress. This, and half a dozen other films, are imitations of the 1961 film Yojimbo. Go to the IMDb entry on Yojimbo and click on “Movie Connection” (on the left under “Fun Stuff”). I wonder if this is the film with the most loose remakes. Samurais, cowboys, Vikings, gangsters . . . Is there anything left to remake it with?
I’d just like to point out that in The Warrior and the Sorceress the leading lady, the delectable Maria Socas, appears topless throughout. Wow.
I always wonder how her agent described the part to her: “Yeah, you get to star with a big American star (coughcough) but there’s just one little thing…” 
“Yojimbo.”
I’ll be damned.
You’re quite right. Never occurred to me… even though I could think of a zillion westerns that used the exact same plot…
Was it sort of a skateboard movie? With some semi-violent game played with a metal sphere?
On a related note, it took me three viewings of A Bug’s Life to realize its plot is a rip-off/homage to The Seven Samurai. (Which is surely up right there in the “most used plot” category. Score two for Kurasowa.)