Yes, but worst of all, it will hurt your environment. According to the U.S. Census, at least 10 percent of onsite septic systems fail. State agencies report that these failing systems are the third most common source of groundwater contamination. Failing septic systems due to lack of, or improper maintenance may result in waste ending up in waterways, or your well, yard or house. It could even end up in someone else’s drinking water. It is not a pleasant scenario, and one that can be avoided with an adequately sized, well maintained, properly working septic system.