As per IS 10500 : (2012) Drinking Water Specification, the permissible limit in the absence of alternate source for total Hardness (as ) mg/L is .....

Question

As per IS 10500 : (2012) Drinking Water Specification, the permissible limit in the absence of alternate source for total Hardness (as ) mg/L is ...........

200

250 1000

600

Solution

Correct option is D

The correct answer is (d).

According to the highly strict Bureau of Indian Standards (BIS) IS 10500:2012 code regulating exact drinking water quality, the "acceptable limit" for total massive water hardness is specifically 200 mg/L.

However, strictly in the "absence of an alternate source," the absolute maximum legally permissible extended limit rockets up to 600 mg/L.

Information Booster

Total hardness is primarily caused by massive concentrations of completely dissolved divalent metallic cations, absolutely overwhelmingly dominated by calcium (Ca2+) and massive magnesium (Mg2+) ions.
Hardness is universally expressed and quantified as totally equivalent milligrams of Calcium Carbonate (CaCO3) perfectly dissolved per single liter of water.
Water exhibiting extreme hardness completely fails to form a stable lather with standard soaps, massively frustrating basic sanitation and generating immense amounts of scum.
When vigorously heated in massive industrial boilers, hard water instantly drops severe, completely solid scale deposits, disastrously crushing thermal efficiency and causing catastrophic explosions.
While consuming extremely hard water generally poses no severe direct medical threat (and may provide dietary calcium), massive 600+ mg/L levels taste intensely foul.
Permanent hardness, strictly caused by massive dissolved chlorides and dense sulfates, completely requires highly advanced ion-exchange resins to effectively remove.
Temporary hardness, strictly caused by massive dissolved bicarbonates, can be rapidly neutralized simply by vigorously boiling the massive water volume.

Additional Knowledge

Option A: 200 mg/L is accurately defined strictly as the absolute optimal "acceptable limit," universally desired when completely pristine water sources are heavily abundant.
Option B: 250 mg/L strictly represents the exact "acceptable limit" exclusively for highly salty Chlorides under the exact same strict IS 10500:2012 water standard.
Option C: 1000 mg/L strictly represents the absolute maximum legally permissible extended limit exclusively for massive Total Dissolved Solids (TDS), definitely not water hardness.
Understanding precise chemical regulatory limits is the absolute bedrock for engineering massive, legally compliant municipal water purification infrastructure globally.