# Building a Playground over a Leach Field? **URL:** \ **Category:** Factual Questions\ **Created:** [April 22, 2013, 12:38am UTC](https://boards.straightdope.com/t/building-a-playground-over-a-leach-field/656356 "2013-04-22T00:38:56Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![wxscooter](https://avatars.discourse-cdn.com/v4/letter/w/9fc348/32.png) [@wxscooter](https://boards.straightdope.com/u/wxscooter)\ **Post date:** [April 22, 2013, 12:38am UTC](https://boards.straightdope.com/t/building-a-playground-over-a-leach-field/656356/1 "2013-04-22T00:38:56Z")
For those whom are familiar with septic tanks, the leach field is basically a long draining area for your sewage (unlike city areas which simply have a sewage line)… Anyway, I would normally not be concerned about a simple playground or kids running around our leach field, except… I want to build a large playground in our yard (more like a raised deck that spans 8’ X 16’ for them to have a small ‘treehouse’ like feel). The only spot that it will fit places it right over the edge over the leach field. I thought it was going to completely clear it until I dug down 27" and hit the protective top layer and then stones… I need to build 6 piers that drop below the frost line (about 36") that will hold this elevated structure… While I know that messing with the leach field is never a smart idea, I was wondering since I’m not actually on any of the main drainage pipes (they’re a few feet deeper into the yard), would I cause major harm to my septic system by building on the very edge of the leach field… The field measures 42’ X 20’ and I’m resting on about the edge by about 1-2’… as a result, it seems 2 of the 6 piers would intersect the right edge of the leach field… Could I remove a 10" diameter section for those 2 piers, as long as it wasn’t near the main drainage pipe? I may have some small leeway in moving the post piers away, but only a few inches at best… I have a feeling that I should probably play it safe, but figured I’d ask any experts if they’ve found/know any ways around my dilemma… Any suggestions are appreciated! ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [April 22, 2013, 2:18am UTC](https://boards.straightdope.com/t/building-a-playground-over-a-leach-field/656356/2 "2013-04-22T02:18:01Z")
you don’t want to compact or put weight on the area above the trench. you could destroy then functioning of that trench at that point. a pier is a lot of concentrated weight which is the destroyer of a field.