- Grains per gallon
- The unit most water test reports use for hardness. Multiplying the grains per gallon by the gallons a household uses each day gives the hardness load a softener must remove, which determines how often it must regenerate. Hardness above a few grains is usually the signal that softening makes sense.
- Ion exchange
- The process in which resin beads swap hardness minerals such as calcium and magnesium for sodium or potassium ions. It is how a household softener works, and the resin has only so much room, so it eventually needs restoring.
- Resin bed
- The column of tiny plastic beads inside a softener tank that holds the exchange sites. Iron fouling, chlorine damage or compaction can weaken it, so loss of capacity is a common service complaint.
- Regeneration
- Restoring a softener's resin by washing it with brine so it releases hardness and takes on sodium again. A cycle includes backwash, brine draw and slow rinse, fast rinse and refilling the brine tank. A timer or a meter that counts gallons can start the cycle.
- Brine tank
- The container that holds salt and the salt solution used in regeneration. Problems such as salt bridges, mushing or a blocked draw line stop brine from reaching the resin, which makes the softener seem to run but not soften.
- Backwash
- Sending water up through a media bed in reverse direction to lift and flush out trapped particles and loosen the bed. Filters and softeners both use it, and a drain too small for the flow can leave the bed dirty.
- Salt efficiency
- How many grains of hardness a softener removes for each pound of salt used in regeneration. Higher figures mean less salt discharged into wastewater, which is why efficiency ratings appear in conservation rules.
- Reverse osmosis
- A treatment in which pressure pushes water through a semipermeable membrane that holds back dissolved salts and many contaminants. It yields treated water for drinking and a reject stream that must go to a proper drain. Higher feed pressure and warmer water generally improve output.
- Total dissolved solids
- The combined amount of dissolved minerals and salts in water, read in parts per million with a conductivity meter. Comparing feed and product readings shows whether an RO membrane is still rejecting properly. A rising product reading is an early sign of a tired membrane.
- Activated carbon
- Highly porous carbon that adsorbs chlorine, tastes, odors and some organic chemicals as water passes through. It is the usual answer for improving taste and odor, but it needs replacement because it eventually saturates. It does not remove hardness minerals.
- Micron rating
- The particle size a sediment filter is built to catch. A smaller number means finer filtration but faster clogging and more pressure loss, so the choice balances cleanliness against flow. Filters are often staged from coarse to fine.
- Point-of-entry unit
- Treatment equipment installed where water enters the building, so every tap receives treated water. Whole-house softeners and large filters are examples, and their connection size must carry the whole demand.
- Point-of-use unit
- A device that treats water at a single outlet, such as an under-sink reverse osmosis system for the kitchen faucet. It serves drinking water only, so installers must handle its drain, air gap and supply connection separately.
- Bathroom group
- A code term for a set of fixtures at one bathroom, counted together rather than one by one. Softener connection tables are entered by the number of these groups, with kitchen and laundry fixtures not adding a size increase.
- Air gap
- An open vertical space between the end of a drain line and the overflow rim of the receptor below it. Because nothing physically connects the two, sewage cannot be drawn back into a softener or RO unit.
- Bypass valve
- A valve set that routes water around a treatment unit for service or when treated water is not wanted. Feeding outside hose faucets through the bypass keeps softened water, and the regenerant that makes it, from being wasted on lawns. Opening it must never allow treated and untreated water to cross-connect.
- Oxidizing filter
- A media filter that converts dissolved iron, manganese or hydrogen sulfide into solid particles and traps them. It is regularly backwashed, and its media must suit the contaminants found in the water analysis. Air or chemical feed may also be part of the system.
- Neutralizing filter
- A tank of mineral media, often calcite, that raises the pH of acidic water as it passes. It protects copper and other piping from pinhole corrosion and may need its media topped up as it dissolves.
- Shock chlorination
- Disinfecting a new or repaired water system by filling it with a strong chlorine solution, letting it stand, and flushing it clean. The dose depends on converting bleach strength into parts per million, and chlorine exposure must be controlled. Let the solution stand for the full contact time before flushing.
- Eyewash station
- A plumbed or self-contained fixture that flushes the eyes after contact with corrosive chemicals. A hose, sink faucet or shower does not count, and it must be reachable in seconds from where salts, acids or chlorine are handled. Know where the nearest one is before opening a chemical container.
