On Fri, 19 Aug 2011 09:26:00 -0500, bud-- wrote:

You might be able to rig a mechanical indicator that shows over the edge
of the tank.

I asked three neighbors this weekend, and, ALL of them have the same
mechanism!

They all have a block of brightly painted wood that is at the outside
bottom of one tank (all tanks are in parallel) when the water is full; and
it slowly rises, a few inches every few hundred gallons, until it's at the
top.

The one thing different is that they all said their wells pump continuously
.... so ... I must have a local problem with water flow.

you could have lights (like a light bulb) at the tank visible
from the house.

I 'guess' there could be a three-light system, green being full, yellow
being half empty, red being lower than that (or something like that), but,
actual levels would be more informative.