It can still help reduce the ISO rating of the entire coverage area if you have an accesible pond. DCNR has grants to install dry hydrants. So while you may not get a discount individially per say, it will still help in the long run. While fire departments bring drop tanks with them, they still need to get the water from somewhere to put in them. The general rule for dry hydrants is to have one installed every three square miles. This means that at a 35mph average with a tanker the trip will take about 6 minutes. Obviously other conditions affect this, but, this is the general rule. The fire department can do drills in rural areas to lower the iso rating also. The more dry hydrants they can show on the books the more it helps them to lower the areas insurance rating.
It is not a must to have a dry hydrant but it is extremely helpful. They can vary in distance from the pond. We have a few hear that are about a hundred or so feet from the water source. The horizontal distance does not affect drafting per say. It is more air to get out when drafting water from a pond but vertical distance from the water is what makes or breaks drafting from a pond. The only limit we have on getting close to the water is the ground leading to it. If it is not a hard surface most departments will not get a rig stuck trying to get water. I have pulled to within one or two feet of the water source in the past. Like I said up top, they must eventually have a source to refill their tankers. That is the reason for all of the ponds and dry hydrants we try to get permission to use. As far as hard suction hose and strainers, all trucks should have these. The only places I never seen them have hard sleeve or strainers has been city areas. It actually bit New Orleans in the seat meat not having this, but thats another story.
Oh, I forgot to add; I work in VA and we just went through an ISO evaluation to lower are rating. I am a driver pump operator assigned to a rural engine company and I occasionally give informational sessions to co-workers and homeowners on rural water issues.