Above ground or underground ? Straight through, or can it be routed so you could subdivide your land later ?
And, to clarify, they offered $30K TO you, not FROM you ?
And what are they feeding, a few homes, subdivision, farm, industrial...?
You might consider a monthly or yearly fee for compensation on top of an initial fee, for several reasons.
Not the least of which is to remain on the books and to address risk, usage, maintenance, and inflation.
They want me to pay $30,000 if I hook up the house I am building to flip. If they had offered me $30,000 in cash I would have probably said show me the money! That is a separate issue from anything I would get in return for them running the pipe through my land, either one or both lots.
It is a mostly residential area with a couple small businesses, they have been hauling water in around me for years as the well drillers made a habit of drilling past the water seemingly to make more money as they get paid per foot, my well works great at 52 feet while all the 600-900 foot wells around me are dry.
I would think the water line would be underground, it would risk freezing above ground here in the winter.
