I would like to have an irrigation system installed for my lawn, but I
don't have unlimited money.

One of neighbors invested tens of thousands of dollar in a "tank farm"
in his basement. He can water his entire 1.5 acre lawn in a couple of
hours, and it's all filtered for iron.

My other neighbor, for whatever reason, doesn't have iron in his water
(we all have well water, btw), so he just got a quote of $3300 for the
outdoor part, and he's already upgraded his well pump and tank, so
he's ready to go.

If I decide to skip the iron filter for irrigation, will that be a
problem? How quickly will the driveway and sidewalk become stained
with rust, and how hard will it be to clean it off?

Is it a bad idea?