appraised value

There is a subdivision going in behind our house. The developer wants to run a sewer pipe through our yard to connect to the main sewer line on the road. Would a 15-20 foot sewer easement on our house deed affect the value of our home? If so, about how much would it affect the value?

My home was built in 1970. I's a all brick ranch with a walkout basement. The property is fenced in with a double gate that allows for car and truck access to the back through the grass. When built they had a garage in the basement. Due to current code the second owners had to board up the...