▁was tes ▁stored ▁in ▁under ground ▁storage ▁t anks ▁and ▁pip es ▁may ▁end ▁up ▁in ▁the ▁ground ▁water . ▁T anks ▁and ▁pip ing ▁leak ▁if ▁they ▁are ▁constructed ▁or ▁installed ▁impro per ly . ▁Ste el ▁t anks ▁and ▁pip ing ▁cor ro de ▁with ▁age . ▁T anks ▁are ▁often ▁found ▁on ▁far ms . ▁The ▁possibility ▁of ▁le aking ▁t anks ▁is ▁great ▁on ▁old , ▁abandoned ▁farm ▁sites . ▁Farm ▁t anks ▁are ▁ex empt ▁from ▁the ▁E PA ▁rules ▁for ▁pet role um ▁and ▁chemical ▁t anks . ▁ ▁Land fill s ▁and ▁waste ▁d umps : ▁Modern ▁land fill s ▁are ▁designed ▁to ▁contain ▁any ▁le aking ▁liqu ids , ▁but ▁flo ods ▁can ▁carry ▁con amin ants ▁over ▁the ▁bar riers . ▁Old er ▁d umps ites ▁may ▁have ▁a ▁wide ▁variety ▁of ▁poll ut ants ▁that ▁can ▁se ep ▁into ▁ground ▁water . ▁ ▁House hold ▁was tes : ▁Im pro per ▁dispos al ▁of ▁many ▁common ▁products ▁can ▁poll ute ▁ground ▁water . ▁These ▁include ▁clean ing ▁sol vent s , ▁used ▁motor ▁oil , ▁pain ts , ▁and ▁paint ▁th inners . ▁Even ▁so aps ▁and ▁d eter g ents ▁can ▁harm ▁drink ing ▁water . ▁These ▁are ▁often ▁a ▁problem ▁from ▁fault y ▁sept ic ▁t anks ▁and ▁sept ic ▁le aching ▁fields . ▁ ▁Le ad ▁and ▁co pper : ▁E lev ated ▁concentr ations ▁of ▁lead ▁are ▁rarely ▁found ▁in ▁source ▁water . ▁Le ad ▁is ▁commonly ▁found ▁in