Try to use non toxic products around your house. Toxic chemicals poured into the ground are harder to purify than non toxic ones.
Try to use water based products. They are the safest.Use low phosphate or phosphate free detergents.
Take unwanted household chemicals to hazardous waste collection centers; do not pour them down the drain. Pouring chemicals down the drain may disrupt your septic system or else contaminate treatment plant sludge.