Drinking water and groundwater sample results are compared to:

Learn more about drinking water PFAS maximum contaminant levels

 The majority of surface water (i.e., waterbody) samples collected are compared to:

Some water supplies draw water from a waterbody, treat the water, and then use it for drinking water.

If surface water samples are collected directly from a waterbody that is also used as a source for drinking water, then surface water samples are compared to:

ppt = parts per trillion

PFAS can get into drinking water when products or wastes containing them are disposed of, used or spilled onto the ground or into lakes and rivers.

PFAS move easily through the ground, getting into groundwater that is used for some water supplies or for private drinking water wells. When released into lakes or rivers used as sources of drinking water, they can get into drinking water supplies.

PFAS released by facilities into the air can also end up in rivers and lakes used for drinking water.

Test results can vary depending on several factors, including:

• the depth of the drinking water wells
• groundwater flow direction, and
• geological characteristics underground

PFAS contamination in groundwater can be found at different depths in the ground depending on the aquifer thickness, type, and whether sand or clay are present.  

Groundwater flows in certain directions and paths, and depending on your home's and drinking water well's location in relation to the PFAS contamination source, your testing results might show different levels of PFAS than your neighbors well.