How far away should my well be from the septic leach field (or drainfield)? At least 100 feet away from the leach field 75% Not sure 25% Get Free Quotes Today! Question: How far away should my well be from the septic leach field (or drainfield)? Top Answer (75% of 4 votes): At least 100 feet away from the leach field. Get Free Quotes Today! Find Local Pros Free Septic System Installation Cost Estimates Related Questions How Much Does It Cost to Put in a Septic Tank? What is an Engineered Septic System? What is a Septic Baffle? What is a Septic Alarm? What is a septic Lid?