Two small rocks about 1" are blocking access to main water shutoff valve in 4-5' vertical pipe about 2 1/2" in diameter. Need to snag them! pipe is outside residence.
Find a PVC pipe cap that is a little smaller than the inside diameter of the 2-1/2" pipe.
Tape or otherwise affix the pipe cap to the end of a length of rod, dowel or other convenient material. The open end of the cap must face away from the main body of the rod.
Fill the cap with sticky wax, Play-Doh, thick grease or a similar substance.
Lower the assembly into the pipe. When it reaches the bottom, press gently to deform the sticky substance around the rock(s) and lift slowly to retrieve them.
Inspired by the old-timey "sounding lead" with a hollow bottom containing tallow, used to measure the depth of water below a ship and simultaneously, the character of the bottom based on whatever sticks to the tallow.
You could try contacting the town to see if they could shut off the water for you. The main water shutoff is usually part of their jurisdiction, and they should be able to help you. Normally the main shutoff has a cover on it which would prevent objects from falling inside. If they are not able to remove the stones, the only other alternative would be for them to dig down to the main valve and replace the shutoff riser. This is definitely not a job you would want to attempt on your own since it connects directly to the water main and you would be liable for damages.