Water Softeners and High Blood Pressure

Extra sodium from tap water adds up

If you live in a small community or rural area, you are probably familiar with water softeners. Water softeners are devices attached to home plumbing systems that are designed to eliminate certain problems that come from having “hard” water - problems like discoloration of tubs and sinks, unpleasant odors/tastes, or stiff, scratchy clothes (after laundering).

Filling the salt tank of a water softener
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Water Softener and a Raise in Blood Pressure

Hard water comes from certain types of wells, and the term “hard” refers to the fact that well water tends to have a rather large amount of dissolved calcium and magnesium. Water softeners work by removing these substances, but to do so they have to add a replacement. Commonly, that replacement is sodium.

In areas with very hard water, the softened water coming from your tap can actually add a significant amount of sodium to your diet. The harder the water, the more sodium the softening system must add to replace the dissolved calcium and magnesium.

In order to figure out how much sodium your softener is adding, you’ll need to contact your local health department, who will be able to tell you the mineral content of your well. You want to ask for the hardness of your water in “grains per gallon.”

You can multiply this number by 8 to find out how much sodium (expressed in milligrams per liter) is added to your water by your water softener. In general, typically softened water contains about 12.5mg of sodium per 8oz glass. If this water were graded according to the same scale the Food and Drug Administration uses for foods, it would be considered “very low sodium.”

If you live in an area with very hard water or tend to drink a lot of tap water, this extra sodium can start to add up. Studies have shown that significantly decreasing sodium intake can lower your blood pressure by up to 8mmHg. Some things you can do to combat sodium in your water include:

  • Switching to a non-salt based softening system
  • Using bottled or filtered water (a simple pitcher filter will work) for cooking and drinking
  • Having a plumber disconnect the cold water system from your softener, so that only hot water (used for bathing and laundry) is softened

Though there are economical ways to eliminate this extra sodium from your diet, remember that the biggest sources of salt in the diet come from processed foods and the salt shaker.

What Causes High Blood Pressure?

Two different types of hypertension or high blood pressure exist primary (essential) hypertension and secondary hypertension. In most adults with hypertension, there's no exact etiology or well-defined cause. These adults have primary hypertension that develops during the course of a lifetime.

Nevertheless, factors like salt in taking in salt-sensitive people, obesity, aging, stress, and insulin resistance (type 2 diabetes) can increase blood pressure in people with essential hypertension.

Secondary hypertension, however, can be traced back to a cause. A minority of people have secondary hypertension. The onset of secondary hypertension is quick. Secondary hypertension can be attributed to the following factors:

  • Thyroid problems
  • Adrenal gland tumors
  • Kidney problems
  • Obstructive sleep apnea
  • Medications (for example, birth control pills, decongestants, and some painkillers)
  • Drugs like methamphetamine or cocaine
  • Alcohol misuse or dependence
3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Walters RM, Anim-danso E, Amato SM, et al. Hard water softening effect of a baby cleanser. Clin Cosmet Investig Dermatol. 2016;9:339-345. doi:10.2147/CCID.S111729

  2. Montasser ME, Douglas JA, Roy-gagnon MH, et al. Determinants of blood pressure response to low-salt intake in a healthy adult population. J Clin Hypertens (Greenwich). 2011;13(11):795-800. doi:10.1111/j.1751-7176.2011.00523.x

  3. Uzu T. Salt and hypertension in diabetes. Diabetol Int. 2017;8(2):154-159. doi:10.1007/s13340-017-0305-3

By Craig O. Weber, MD
Craig O. Weber, MD, is a board-certified occupational specialist who has practiced for over 36 years.