I am about to replace my 4" deep well pump and control box (deep is a relative term here, it is only about 25' down.)

The new pump has 4 wires, Red, Yellow, Black, and Green.

There is no ground wire in the cable running out to the well. It was installed 40 years ago, and I guess, back then in the dark ages, they didn't think it was needed.

The well casing is concrete and 18" dia.

I have 2 questions:
#1 is it required the pump be grounded? There is a heavy ground wire clamped to the copper pipe near the water heater so the water system is grounded.

#2, If I want to ground it, can I just attach the green wire to the metal pipe between the casing and the pitless adapter?

I think it is bad practice to ground things in 2 places (at the pump, and at the water heater) as eddy currents flow and erosion may eat stuff like pipes and pumps.

Thoughts? Maybe someone can direct me to codes? I live in NW WA.

Thanks, Mark.