Total Hardness in Drinking Water: Health Risks, Sources, and How to Remove It
Total Hardness is an inorganic constituent in drinking water. The Environmental Protection Agency (EPA) Maximum Contaminant Level (MCL) for this constituent is 500 mg/L. It is typically monitored for aesthetic reasons rather than direct health risks.
Health Effects
There are no direct health effects associated with consuming water with Total Hardness. Instead, elevated hardness levels cause scaling in plumbing fixtures and appliances. It also causes soap inefficiency, making it harder to lather and clean effectively.
How Total Hardness Gets Into Tap Water
Total Hardness enters drinking water supplies from natural mineral deposits. As water flows underground, it dissolves minerals from rocks such as limestone. This natural geological process is the primary source of hardness in water.
How to Remove Total Hardness From Your Water
Common treatment methods to address Total Hardness include water softening. Reverse osmosis systems can also be used to remove these dissolved minerals. These treatment technologies help prevent scale buildup and improve soap performance.
Should You Test Your Water?
You can check the hardness of your water by reviewing your local water utility's consumer confidence report or searching on WaterQ. If you rely on a private well, you can have your water tested by a certified laboratory. You can also look up your local water system on WaterQ or check the Total Hardness data page for reported levels in your area.
Frequently Asked Questions
Is Total Hardness dangerous in drinking water?
No, Total Hardness does not have direct health effects and is not dangerous to consume. Its impact is limited to aesthetic issues, such as pipe scaling and soap inefficiency.
How does Total Hardness get into tap water?
Total Hardness gets into tap water naturally as groundwater dissolves minerals from limestone and other geological deposits.
How can I remove Total Hardness from my water?
You can remove Total Hardness by installing a water softening system or using a reverse osmosis system.
Source: EPA National Primary Drinking Water Regulations and WaterQ National Database. For more contaminants, visit our contaminant library.
What actually removes hard water (calcium and magnesium)
Hardness is dissolved calcium and magnesium, and no carbon filter removes either. An ion-exchange softener is the only whole-house fix that actually lowers hardness — it is the same chemistry an ion-exchange pitcher uses, just sized for the house rather than a jug, and pitcher cartridges exhaust very fast in genuinely hard water. Salt-free "conditioners" do not remove hardness at all; they change how the minerals crystallize so they scale less, which helps appliances but will not change a hardness test result. Reverse osmosis handles hardness too, but only at the one tap it is plumbed to.
Works
- Ion-exchange water softenerThe only real fix for hard water. Also very effective on radium.
- Reverse osmosis (NSF 58)The broadest removal available at home: arsenic, nitrate, fluoride, PFAS, TDS.
- Ion-exchange pitcherDrives total dissolved solids near zero, but cartridges exhaust fast.
Will not fix this
- Basic activated carbon (NSF 42)
- Carbon certified for lead (NSF 53)
- PFAS-rated carbon (NSF 53 PFOA/PFOS or P473)
- UV disinfection (NSF 55)
- Boiling Makes it worse — evaporation concentrates what's left behind.
Options that carry the right certification
Ordered cheapest-adequate first. Prices are indicative bands and move often.
| Product | Certification | Upfront | Per year | |
|---|---|---|---|---|
| Fleck 5600SXT Metered SoftenerWhole house | Standard metered ion-exchange softener valve, the long-time reference design.Catch:Adds sodium to your water and needs a drain plus salt refills. Does nothing for lead, PFAS or nitrate. | $600–900 | $60–150 | Check price |
| APEC ROES-50 EssenceUnder-sink | Built with WQA-certified components to NSF/ANSI 58.Catch:Needs an under-sink drain connection and a spare hole for the dedicated faucet. Strips minerals — some people dislike the flat taste. | $180–240 | $50–80 | Check price |
| ZeroWater 5-Stage PitcherPitcher | NSF/ANSI 42 and 53 certified for lead and chromium; drives TDS toward zero.Catch:Cartridges exhaust quickly in high-TDS or hard water, which is exactly where people buy it — running cost is the highest of any pitcher. | $30–50 | $100–180 | Check price |
Certification listings change. Before buying, confirm the current listing for the exact model in the NSF certified products database — a manufacturer's marketing page is not a certification. WaterQ earns a commission on purchases made through these links at no extra cost to you; see our affiliate disclosure. This is general information, not medical or engineering advice.
For a full breakdown of certifications, running costs and the models worth considering, see our buying guide for hard water (calcium and magnesium).