Hard water, i.e., water with minerals in it, tends to be healthy.  The process of water softening is unhealthy, although some hard waters have unpleasant odors and tastes.  I would recommend not using a water softener unless truly necessary.  Water softening removes calcium and magnesium and adds sodium.  Sodium is a major culprit behind high blood pressure.  By contrast, numerous studies have shows health benefits to individuals consuming larger amounts of magnesium.  Higher calcium intake, except in older men, also tends to be beneficial. 

Cardiac Mortality Decreased in Taiwan by Hard Water: After adjustment for the urbanization index, coronary mortality in municipalities with soft water was estimated to be 9.6% higher than that in municipalities with hard water. The weighted multivariate-adjusted regression coefficient indicated a decrease of 0.053 in standardized mortality ratios (SMRs) for every 100 mg/L increase in total hardness in drinking water after allowing for the urbanization condition. Taiwan study. : J Toxicol Environ Health 1996 Sep;49(1):1-9

Cardiac Mortality Decreased in England by Hard Water: After adjustment for other factors, soft water areas (around 0.25 mmol/l) have a 10-15% higher cardiovascular mortality that areas of medium hardness (around 1.70 mmol/l) whereas any further increase beyond 1.70 mmol/l has little extra lowering effect on cardiovascular mortality. Sci Total Environ 1981 Apr;18:25-34

Cardiac Mortality Decreased in Netherlands in Communities with Hard Water: In 1975 central water softening was discouraged by the Public Health Council because of the statistical negative association found in 23 communities between the hardness of drinking water and death rate from Ischemic Heart Disease over the period 1958-1970. The release of metals (Pb and Cu) from household water distribution pipes was positively correlated with water calcium. Food looses more Ca and Mg when it is cooked in soft water as compared to cooking in hard water. Water hardness and mortality in the Netherlands. Zielhuis RL, Haring BJ. Sci Total Environ. 1981 Apr;18:35-45.

Cardiac: Heart Attacks Reduced by Hard Water in Finland: In a careful study of 18,946 men ages 35-74 with the first AMI attack, a one unit increment in water hardness decreased the risk of AMI by 1%. Geochemical elements in ground water included in this study did not show a statistically significant effect on the incidence and spatial variation of AMI, even though suggestive findings were detected for fluoride (protective), iron and copper (increasing). This study confirms findings from earlier observations of the inverse relation between water hardness and coronary heart disease. Geochemistry of ground water and the incidence of acute myocardial infarction in Finland. Kousa A, Moltchanova E, et al. Geological Survey of Finland, Kuopio, Finland. J Epidemiol Community Health. 2004 Feb;58(2):136-9

Colon Cancer Decreases with Hard Water: All eligible rectal cancer deaths (986 cases) of Taiwan residents from 1990 through 1994 were compared with deaths from other causes (986 controls). A significant negative relationship between drinking water hardness and rectal cancer mortality. Odds ratio were 1.24 and 1.38, respectively, for exposure to moderately hard water and soft water compared with the use of hard water. Rectal cancer mortality and total hardness levels in Taiwan's drinking water. Yang CY, Tsai SS, Lai TC, Hung CF, Chiu HF. Environ Res 1999 May;80(4):311-6

Eczema Increased in Primary School by Hard Water: Lancet 1998 Aug 15;352(9127):527-31 reports a study of 7,500 primary and secondary school kids. The 1-year period prevalence of eczema was 17.3% (261/1509) in the highest water-hardness category and 12.0% (94/786) in the lowest (adjusted odds ratio 1.54; p <0.001). The corresponding values for lifetime prevalence were 25.4% (384/1509) and 21.2% (167/786); OR 1.28, p=0.02). Eczema prevalence trends in the secondary-school population were not significant.

Fluoride Removed by Point of Use Filtering: Point-of-use water conditioning systems attach at the sink to provide the user with protection from certain water contaminants. All point-of-use water conditioning systems tested caused a large reduction in fluoride (P < .001): activated carbon filter (81%), reverse osmosis system (84%), and distillation unit (99%). The effect of point-of-use water conditioning systems on community fluoridated water. Brown MD, Aaron G. Fort Campbell, KY. Pediatr Dent. 1991 Jan-Feb;13(1):35-8.

Gastric Cancer Decreased by Hard Water: There was a significant negative relationship between drinking water hardness and gastric cancer mortality in this study. Odds ratios were 1.16 and 1.65, respectively, for exposure to moderately hard water and soft water compared with the use of hard water. The study compared 6,766 cases vs. controls in Taiwan in early 90s. Arch Environ Contam Toxicol 1997 Oct;33(3):336-40

Gingivitis: Soft Water Linked to Harm: In a study of adults from the third National Health and Nutrition Examination Survey (NHANES III), those using soft water had a significantly higher risk of periodontitis (p < 0.05), adjusting for confounders. Smoking further increased this risk. Use of water 'softening and conditioning systems' significantly increases the risk of periodontitis: smoking considerations. Wood N, Johnson RB. University of Mississippi. J Periodontal Res. 2004 Dec;39(6):367-72.

Kidney Stones Increased by Hard Water: As compared with both tap and soft water, hard water was associated with a significant 50% increase of the urinary calcium concentration in the absence of changes of oxalate excretion. 18 patient study. Nephron 1999;81 Suppl 1:66-70

Lead Levels Decreased by Hard Water: Water lead levels fell after hardening was introduced whereas there was a small rise in water lead levels in a control area monitored over the same time. The blood lead levels of residents fell after hardening and the fall was slightly greater than would have been predicted on the basis of the change in water lead levels. This suggests that lead is less well absorbed from hard water than from soft water. Following hardening there was a significant fall in mean blood lead level of subjects living in houses which had initially had negligible amounts of lead in the water. This suggests that hard water may interfere with the absorption of lead from sources other than water. Hum Toxicol 1983 Oct;2(4):645-8

Magnesium and Calcium Main Water Components, Help Longevity: The magnesium and calcium contents of drinking water for specific geographic regions of the U.S.A. is presented. These data show a strong positive correlation between low magnesium content and decreased longevity, and between high calcium and magnesium content and increased longevity. Chemical qualities of water that contribute to human health in a positive way. Hopps HC, Feder GL. Sci Total Environ 1986 Oct;54:207-16

Sodium Added by Water Softeners: In a study of 59 water samples that had passed through various home water softeners and the sodium concentration of 5 samples from 4 different local municipal sources, the softened well water had 278 mg/L sodium with 17% of households with sodium levels greater than 400 mg/L. The municipal, nonsoftened water was 110 mg/L. Sodium concentration of water from softeners. Yarows SA, Fusilier WE, Weder AB. University of Michigan. Arch Intern Med. 1997 Jan 27;157(2):218-22. Ed: A person trying to consume a maximum of 1500 mg of sodium per day, the ideal maximum according to the DASH research, and consuming 8 cups of water via cooking with tap water or using it in drinking, would already have 33% of the daily limit just from the water.  Water softeners are bad for humans.

Thomas E Radecki, M.D.

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