Silica in Drinking Water

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What is Silica?

Silica is a hard, glassy mineral and one of the most abundant elements found in the Earth’s crust. Just like calcium, magnesium and other major minerals, silica is found in groundwater supplies at varying concentrations, depending on the surrounding rock. Continue reading to learn more about silica and the effects it can have on your water quality.

How Does Silica Get Into Drinking Water?

As water passes through the Earth, it dissolves silica from rocks and minerals. Because of this, most—if not all—water supplies contain some amount of dissolved silica. It’s also found in certain foods like oats, rice, strawberries and more.

The Effects of Silica in Water

There are two different forms of silica that end up in water: reactive silica and colloidal silica. Reactive silica is a very weak acid that dissolves in water, while colloidal silica has a glass-like structure that can damage surfaces, glassware and fixtures. While both forms of silica are harmless when ingested, they can also leave behind cloudy or milky spots on surfaces and fixtures, as well as white, chalky build-ups of minerals called scale.


Removing Silica from Water

There are multiple treatment options for removing silica from water, on both residential and commercial levels, based on identifying what type(s) are found in your water. After determining this through a free water test, here are the solution options. 


Ultrafiltration systems have extremely fine membranes, giving them the ability to filter out solid matter on a microscopic level. Because colloidal silica is suspended in water, ultrafiltration is great for its removal. However, these systems cannot effectively remove reactive silica. A challenge of this silica removal option is being able to determine the type of silica in your water as there are not feasible testing options to determine silica type and particle size.  For this reason, we recommend treatment options that either sequester the silica preventing etching or removing silica through a process of reverse osmosis.

Ion Exchange

Ion exchange water softener systems remove dissolved ions from water, making them perfect to deal with the negative charge of reactive silica. With a negative charge, anion resin is the required media. Occasionally, these systems will need additional crystalline salt to continue working, which is something Kinetico can help with/deliver to you. Additionally, due to the constraints of testing, it is difficult to determine the silica type and whether or not ion exchange will be effective for the type of silica present in your water.

Reverse Osmosis

Reverse osmosis water purification systems have the advantage of removing both molecules and ions from water, effectively dealing with both reactive and colloidal silica in the process. At over 99% removal rates for all contaminants, RO is one the best methods of treating for silica while also providing you with the best water possible. This solution is ideal for drinking water quality. Some pre-treatment is still required for colloidal silica. RO systems also need annual maintenance and eventual membrane replacement, but Kinetico can advise on/help with this.  


Silica sequestration systems do not use filtration, ion exchange, or reverse osmosis to remove silica but sequester the silica by using a sequestering agent to prevent etching and scale. These systems will require replenishment of the sequestering media over time which will vary depending on water use. Due to the fact that these systems introduce a sequestering agent to the water, they are not ideal systems for drinking water where high levels of purity are recommended.  

Keep Your Water Palatable and Your Appliances Clean

If you think silica could be causing damage in your home, schedule a free water test with one of our water experts today.