Search city, ZIP, contaminant⌘KFind my water
Water property guide

Water Characteristics in Tap Water

Water characteristics describe properties such as hardness, pH, or dissolved solids. They often affect taste, scaling, corrosion, or treatment choices rather than act as contaminants.

Check my local water

2 compound guides0 with a federal MCL6 treatment methods named

What are water characteristics?

A grouping for navigation, not a shared effect

These records help explain how water behaves in plumbing and treatment. They are grouped for navigation, not to imply a shared health effect.

Many characteristics have aesthetic, operational, or secondary guidance instead of a health-based federal maximum. The individual record states the relevant context. Water hardness (dissolved calcium and magnesium, usually reported in grains per gallon) is the most common of these.

Hardness sits outside the federal drinking-water datasets: it comes from a utility’s own annual report rather than EPA monitoring. PurityMap has a sourced hardness value for only 42 cities so far, which is why most city reports mark hardness as pending rather than guess at a number. Hardness is an aesthetic and operational property (it causes scale, spots, and reduced soap lather), not a regulated health limit, so the decision to soften water is about comfort and appliance life, not safety.

Sources named in the compound records
  • Groundwater through limestone/mineral formations
  • Plastic packaging and litter breakdown
  • Synthetic textile fibres
  • Tyre and road wear
  • Plastic distribution and bottling
Published compound guides

Two published compound guides

None has a federal health limit; each record states its own context.

Identifier not publishedHard waterCalcium and magnesium hardnessHardness is dissolved calcium and magnesium picked up from rock and soil. It is an aesthetic and plumbing consideration, not a health-based contaminant.NoneNo federal limitRead compound evidence →Identifier not publishedMicroplasticsMicroplastic particles (< 5 mm)Microplastics are plastic fragments smaller than 5 millimetres (down to microscopic nanoplastics) that shed from packaging, textiles, tyres and the breakdown of larger plastic waste. They are an emerging contaminant: increasingly detected in tap and bottled water, but not yet federally regulated in drinking water.NoneNo federal limitNo federal drinking-water limit (unregulated as of 2026)Read compound evidence →
How to read a local result

Four checks before you act

  1. STEP 1Identify the named analyte

    A family name may contain compounds with different standards and health contexts.

  2. STEP 2Keep the measurement attached

    Read the value with its unit, qualifier, sampling period, reporting limit and source.

  3. STEP 3Compare only with the stated reference

    PurityMap does not turn unlike compound results into a family score or safety verdict.

  4. STEP 4Verify the treatment claim

    The product certification must name the compound or reduction claim.

Treatment capabilities in the published records

Six methods, each named by the compound guides

A technology name is only a starting point. Confirm the product’s certification names the compound before choosing equipment.

Choosing a water softener for hard water
  • Fine activated-carbon block filtration

    Named by 1 of 2 compound guides in this family.

    MP
  • Ion-exchange water softener

    Named by 1 of 2 compound guides in this family.

    CaCO₃
  • Nanofiltration

    Named by 1 of 2 compound guides in this family.

    MP
  • Reverse osmosis

    Named by 1 of 2 compound guides in this family.

    MP
  • Reverse osmosis (point-of-use)

    Named by 1 of 2 compound guides in this family.

    CaCO₃
  • Salt-free conditioner

    Named by 1 of 2 compound guides in this family.

    CaCO₃
Related intelligenceAssembled from PurityMap’s governed contaminant records. How we analyze water data
All contaminantsFind my waterTreatment technologiesWater intelligence mapPurityMap methodology