Just a quick note from a pond owner and a Fire Chief. Theo said it best. You have to have a road to the hydrant strong enough to handle a heavy truck. Fires happen in bad weather. Dry hydrants are nice only if they are installed right and maintained. My department has used them and they worked fine. In my area, we have city water now and only have a small area that does not. Its up to you. Yes, some insurance companies do give deductions. My rule of thumb is if you can not get a house fire out with about 2000-4000 gallons of water, you will not be saving much. Most department carry that much on their first assignment. Last week we had a fire in 30 mph wind. We worked very hard to save a small end of the house. This saved the family alot of old family memories.