Welcome to brain Stuff from how stuff works dot com where smart Happens. Hi, I'm Marshall Brain with today's question, how does a water softener work? We call water hard if it contains a lot of calcium or magnesium dissolved in it. Hard water causes two problems. First, it can cause scale to form inside of pipes and water heaters and tea kettles. The calcium magnesium participate out of the
water and stick to things. Eventually pipes can become completely clogged. Second, the calcium and magnesium react with soap to form a sticky scum and also reduces the soaps ability to lather. Since most of us like to wash with soap, hard water makes a bath or a shower less productive. The solution to hard water is either to filter the water by distillation or reverse osmosis to remove the calcium and
magnesium altogether, or to use a water softener. Filtration would be expensive to use or all the water in a house, so a water softener is usually the less expensive solution. The idea behind a water softener is simple. The calcium and magnesium ions in the water are replaced with sodium ions. Since sodium does not precipitate out in pipes or react badly with soap. Both the problems of hard water are
completely eliminated. To do the ion replacement, the water in the house runs through a bed of small plastic beads or through a chemical matrix called zeolite. The beads or zeolite are covered with sodium ions. As the water flows past the sodium ions, they swap places with the calcium and magnesium ions. Eventually the beads or zeolite contain nothing but calcium and magnesium and no sodium, and at this point they stop softening the water. It's then time to
regenerate the beads or zeolite. Regeneration involves soaking the beads or zeolite in a stream of sodium ions. Salt is sodium chloride, so the water softener mixes up a very strong Brian solution and flushes it through the zolder beads. This is why you load up a water soften or with salt crystals. The strong Brian displaces all the calcium and magnesium that is built up on the beads and
replaces it again with sodium. The remaining Brian plus all the calcium and magnesium is flushed out through a drain pipe. Regeneration can create a lot of salty water, something like twenty five gallons for each cycle. Do you have any ideas or suggestions for this podcast? If so, please send me an email at podcast at how stuff works dot com. For more on this and thousands of other topics, go to how stuff works dot com.