EPA Basic Well Information

The EPA has a specific web page that provides detailed information about types of well construction and well siting considerations to keep your well free from contaminants.

The Centers for Disease Control (CDC) "Well Siting & Potential Contaminants"( Link NO Longer Available)  has a link that includes a diagram with minimum safe distances from wells and potential contaminants.
 
Penn State Cooperative's " Guide to Private Water Systems in PA (PDF)"

This document provides information for private water systems in Pennsylvania about the proper construction and maintenance of private wells, springs, and cisterns. It includes information about estimating water needs, protecting your water system, potential sources of pollution, common contaminants, and treatment information.

The Centers for Disease Control (CDC) ( Link NO Longer Available) has some basic information on wells and construction.
 
The Pa Department of Conservation and Natural resources (DCNR) Well Construction (PDF) DCNR Bureau of Geological Survey has recommendations for well construction.
 

DCNR's Geological Survey Groundwater webpage contains information about items such as bedrock aquifer characteristics and well construction information.

The National Ground Water Association has a page for well owners; the finished well checklist discusses what to look for following well construction.