Water treatment system Photo: Tom McCarty, Penn State
The whole house sediment filter is the most common treatment in Pennsylvania homes. This filter removes particulates from the water to improve water clarity. Such a filter improves treatment effectiveness and reduces maintenance for other treatment systems after it. Follow manufacturer's instructions for changing the filter.
There are also automatic backwashing filter systems that can backwash media automatically and require little maintenance. These filters are fitted with different media for removal of sediment, tastes and odors, iron and manganese, volatile organic compounds (VOCs), and arsenic. Periodic laboratory testing is recommended to ensure the treatment system is working properly. Such units require periodic replacement of the filter material once the media bed has reached its absorption limit. Arsenic, VOCs, and certain other hazardous contaminants require special disposal of the spent media bed. Qualified water treatment service providers or manufacturer recommendations can guide the frequency of periodic water testing. Always follow the manufacturer's recommendations for maintenance.
Continuous disinfection systems treat an existing bacteria problem or safeguard against potential bacterial contamination. An ultraviolet sterilizer or UV light installed where the water enters the house (Point of Entry or POE). The clearer the water, the more effective the UV light is. Pre-treatment by water filtration is necessary to remove particulates that could block UV light from killing bacteria. There is a quartz sleeve around the lamp that must be kept clean and the lamp must be replaced annually.
Acid neutralizing systems are used to reduce lead where groundwater is in the acid water range (pH 5.0 to 7.0). Corrosive water can slowly cause any lead and copper to leach from pipes, fixtures, and solder, particularly in older (pre-1990s) homes.
Two types of systems neutralize corrosive water:
- Calcite (calcium carbonate) media in an automatic backwashing filter requires additional calcite be added annually and total replacement of the calcite every two or three years.
- Injecting sodium carbonate (soda ash) into the water with a feed pump system requires mixing solution to fill the pump two or three times a year.
Ion exchange is a POE device such as a water softener. The salt used to backwash these systems must be replenished periodically. Water softeners can run for years with minimal maintenance, but particulates in the water can cause clogging or other system problems. Excess nitrate, which can endanger infants, is also removed using ion exchange, but uses a different resin and compound to regenerate the resin than water softening. Maintenance for ion exchange systems will vary depending on what pollutant is being treated.
Reverse osmosis (RO) systems that treat water at the point of use (POU) are commonly installed under the kitchen sink with their own tap. Coupled with granular activated carbon filters, RO effectively removes many substances that cause water quality problems. Be sure to check manufacturer's specifications to know the RO unit is addressing the contaminant you need removed. The filters need to be replaced once or twice annually depending on water conditions and manufacturer recommendations. The RO membrane can last for years.
Always base the installation of water treatment equipment on water test results from a state accredited water testing laboratory. There is no point in fixing a problem you don't have. Once you decide to install equipment, decide who will perform the routine maintenance of your water treatment system(s). If you decide not to attempt maintenance yourself, use a qualified professional.
Adapted from Residential Water Treatment Equipment Maintenance, www.wellowner.org.