Reference Charts

Dense, citable tables: hardness classification in grains and parts per million, softener sizing and salt dosage, regeneration frequency, resin capacity, filter housing sizes, micron ratings, fixture flow rates, the NSF/ANSI standard numbers and what each one covers, EPA primary and secondary limits, iron and manganese treatment thresholds, ultraviolet dose and membrane output.

18 pages in this section.

Testing

• EPA Drinking Water Limits Chart The EPA's enforceable primary drinking water limits in one chart, including why lead has no MCL and why nitrate units have to be read carefully.
• Secondary Drinking Water Standards Chart The EPA's secondary drinking water standards for iron, manganese, TDS, pH and more, and why hardness has no standard of any kind, primary or secondary.
• TDS Chart The EPA secondary standard for TDS, typical TDS ranges, why TDS measures conductivity rather than hardness or safety, and its genuine use confirming RO rejection.
• Water Treatment Glossary Plain, one-sentence definitions of 46 water treatment terms, from grain per gallon and salt efficiency through reverse osmosis, UV dose and EPA regulatory terms.

Filtration sizing

• Filter Micron Size Chart The micron scale from 0.5 to 50, what absolute and nominal actually mean, particle sizes each rating stops, and the sediment staging chart by water source.
• Fixture Flow Rate Chart Federal maximum fixture flow rates under the Energy Policy Act, WaterSense figures where they exist, and how simultaneous fixture use adds up to peak demand.
• Whole House Water Filter Size Chart Whole house filter housing sizes from standard 2.5 inch through Big Blue 4.5 inch, matched against peak flow by bathroom count, and why a standard housing chokes flow.

Softening

• Grains Per Gallon to PPM Conversion Chart The full grains per gallon to ppm and mg/L conversion chart, plus German and French degrees, for reading any lab report or imported softener manual.
• Water Hardness Chart The USGS water hardness chart in grains per gallon and mg/L, with the plain fact most sites skip: there is no EPA limit for hardness of any kind.
• Water Softener Regeneration Frequency Chart A water softener regeneration frequency chart by nameplate size and hardness, plus the trade's 3 to 14 day target window and the reserve behind it.
• Water Softener Resin Capacity Chart A resin capacity chart showing how nameplate ratings equal resin volume times 32,000 grains at maximum salt dose, and what real capacity looks like below that.
• Water Softener Salt Dosage Chart A water softener salt dosage chart showing exactly how capacity and salt efficiency trade off, from 6 to 15 pounds per cubic foot of resin.
• Water Softener Sizing Chart A water softener sizing chart by household size and measured hardness, using working capacity at an efficient salt dose rather than the nameplate ceiling.

Well water iron

• Iron and Manganese Treatment Chart Which oxidizing media treats iron and manganese, the published pH window each one needs, and why iron bacteria needs shock chlorination, not a filter.

Filtration standards

• NSF/ANSI Standards for Water Treatment, Explained What each NSF/ANSI water treatment standard actually covers, from 42 aesthetic effects through 372 lead content, and why the number matters more than the logo.

pH and acid neutralization

• pH and Corrosion Chart The EPA's 6.5 to 8.5 pH range, what low pH corrosion actually looks like, and the neutralizing media chart from calcite through soda ash injection.

Reverse osmosis

• Reverse Osmosis Membrane Output Chart Why a rated reverse osmosis membrane rarely produces its rated GPD at home, the pressure and temperature grid that explains it, recovery, drain ratio and tank drawdown.

Ultraviolet disinfection

• UV Dose Chart NSF/ANSI 55 Class A and Class B UV dose requirements, how delivered dose falls as flow increases, and why an undersized UV system fails silently.

Researched, not professional advice. Everything in this section is compiled from published standards, regulatory limits, manufacturer specifications and owner-review consensus, not hands-on testing. Nothing here diagnoses a water problem or says any product makes water safe to drink. Published figures and rules of thumb are labeled separately wherever both appear, and where a published figure does not exist we say so rather than estimating one. Test your water first, and treat bacteria, nitrate, lead, arsenic and PFAS as laboratory and professional territory rather than shopping decisions.