The Importance of Home Water Filtration of Sulfates in Drinking Water

Sulfates are formed due to a combination of sulfur and oxygen and are a part of naturally occurring minerals in some soil and rock formations that contain groundwater. The mineral dissolves over time and is released into groundwater. Sulfates can also be found in rainwater which is a result of industrialization and burning/ combustion of fossil fuels. Point sources include sewage treatment plants and industrial discharges such as tanneries, pulp mills, and textile mills. Runoff from fertilized agricultural lands also contributes sulfates to water bodies. Sulfur-reducing bacteria, which use sulfur as an energy source, are the primary producers of large quantities of hydrogen sulfide. These bacteria chemically change natural sulfates in water to hydrogen sulfide. Sulfur-reducing bacteria live in oxygen-deficient environments such as deep wells, plumbing systems, water softeners and water heaters. These bacteria usually flourish on the hot water side of a water distribution system.

Hydrogen sulfide gas also occurs naturally in some groundwater. It is formed from decomposing underground deposits of organic matter such as decaying plant material. It is found in deep or shallow wells and also can enter surface water through springs, although it quickly escapes to the atmosphere. Hydrogen sulfide often is present in wells drilled in shale or sandstone, or near coal or peat deposits or oil fields. Hydrogen sulfide gas produces an offensive “rotten egg” or “sulfur water” odor and taste in the water. In some cases, the odor may be noticeable only when the water is initially turned on or when hot water is run. Heat forces the gas into the air which may cause the odor to be especially offensive in a shower.

Sulfate minerals can cause scale buildup in water pipes similar to other minerals which can corrode plumbing materials and deteriorate their shelf life. Consumption of water with high sulfates may be associated with a bitter taste in water that can have a laxative effect on humans and young livestock. Elevated sulfate levels in combination with chlorine bleach can make cleaning clothes difficult.  Sulfur-oxidizing bacteria produce effects similar to those of iron bacteria. They convert sulfide into sulfate, producing a dark slime that can clog plumbing and/or stain clothing. Blackening of water or dark slime coating the inside of toilet tanks may indicate a sulfur-oxidizing bacteria problem. The maximum contaminant level set by WHO is 250 mg/L. 



Reverse Osmosis is one of the most common and effective methods used for treatment and removal of sulfates in drinking water. A whole-house reverse osmosis system pushes water through a membrane with tiny pores. The membrane removes several contaminants, including sulfate, while allowing water to pass through. Reverse osmosis usually removes between 93 and 99 percent of the sulfate in drinking water, depending on the type of treatment unit. 

The iSpring RCC7AK-UV is a 7-stage, under-sink mounted Reverse Osmosis system suitable for clear drinking water and cooking purposes. The RCC7AK-UV features an extra UV ultraviolet stage. Though not usually necessary with municipal-treated water, this stage is particularly important in treating water from wells, streams, lakes and other natural water sources. Some of the best features of this system are listed as follows:

  • 3 Pre-filters: PP sediment filter, Carbon KDF (GAC) filter, and Carbon block (CTO) filter remove large contaminants like sediment, chlorine and chloramines.
  • The heart of the system is the Reverse Osmosis (RO) filter that removes contaminants down to 0.0001 microns – so small that only water molecules can squeeze through but virtually nothing else.
  • Fine GAC filter provides final polishing before the filtered water is delivered to the faucet.
  • An Alkaline Remineralization filter restores healthy minerals and a natural alkaline balance.
  • With its advanced 11 watt UV stage, the RCC7AK-UV is a suitable option to filtering well water and other problem water sources like water from lakes and streams. The unique flow sensor switch turns the UV unit on and off automatically with water flow, saving power and lengthening the life of the UV lamp.
  • Quality components ensure reliability and low maintenance for many years to come. Clear see-through 1st stage housing makes filter inspection a snap. Feed Water pH – 3.0 -11.0. Feed Water Pressure – 45-70 psi. Feed Water Temperature- 40-100 F (4 – 38 C)


Table 1 – List of Preliminary Contaminants Removed by the iSpring RCC7AK-UV system


The presence of Sulfates and Sulfur compounds such as Hydrogen Sulfide in drinking water can cause impact on the health of humans and livestock and also be detrimental to the shelf life of home appliances such as dishwasher and household plumbing. It can also cause nuisance in performing daily chores such as washing laundry and cleaning dishes by leaving black-stained marks on the clothes and utensils. The iSpring RCC7AK-UV Reverse Osmosis System offers a great solution to eradicate these issues caused due to high sulfates in drinking water. 

Saniwater specializes in educating their customers about most effective treatment solutions for their drinking water concerns. The skilled technicians at Sani Water will help with the installation and provide guidance with respect to maintenance of the Reverse Osmosis system. 




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Meet our Expert

Abhiram Satyadev has a Masters in Environmental Engineering at Drexel University in Philadelphia, Pennsylvania, an MBA at Goldey Beacom College in Delaware, and a Masters Certificate in Standford University. He is currently the Program Manager, Potomac Interceptor for the DC Water in Washington DC. He is responsible for developing, implementing, and maintaining the Potomac Interceptor Renewal Facility specifically including operation and maintenance of odor control facilities at the Potomac Interceptor Sites and Pump Stations.

With Saniwater, he serves as our Research and Development Consultant and provides us with insights into his expertise. Read his section here on to know more.