SepticSmart: Determining Risk

Risk Factors of Unapproved Septic Systems

Unapproved septic systems have not been reviewed by public health professionals; therefore, there is no guarantee that they are constructed to current standards, and thus, they may be more likely to have negative water quality impacts.

Density of Septic Systems

Pollution from septic systems in urban or semi-urban watersheds where there is a density of systems have been identified by local, state, and federal agencies as an area of concern. Few current management tools are applied to them, potentially compounding their risk.

Age of Septic Systems

The age of systems is an important factor to consider when dealing with an onsite wastewater system (OWS), or septic system. There are two factors when dealing with age:
  1. Every system has a limited life
  2. The older the system, the more likely that it does not meet adequate wastewater treatment standards.

Distance to Groundwater

When a septic system is not provided with enough filtering soil between the bottom of the system and groundwater (distance to groundwater), the groundwater can be negatively affected.

Drinking Water

Domestic wells and private drinking water sources can become contaminated by septic systems.


Generally, septic systems are best used on large, relatively level, well-drained lots with deep, moderately permeable soil.


The steeper the slope, the greater the risk of septic system failure.

Distance to Surface Water

The greater the distance between surface water (i.e., creeks, streams, rivers, and lakes) and a septic system, the smaller the chance of surface water contamination.

If you own and operate a septic system, you can help to protect our water by properly maintaining an approved system.Check your system today.

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