Hard water in North County homes: what it does and what you can do

How is water hardness measured?

Hardness is mostly dissolved calcium and magnesium. Water quality reports usually list it in milligrams per liter (mg/L) as calcium carbonate, and softener sellers usually talk in grains per gallon (gpg). One grain per gallon is roughly 17 mg/L, which is why a district that reports 230 mg/L also describes that as about 13.5 grains.

The U.S. Geological Survey uses this scale:

USGS notes that utilities generally try to stay out of the very hard band because it causes scaling in equipment and means using more soap and detergent.

What do local water reports say?

Only some of the utilities in this area publish a hardness figure that we have confirmed. Here is what their reports state:

The wide Vista Irrigation District range makes sense once you look at where the water comes from. The district blends local water from the Lake Henshaw watershed and its well fields with imported Colorado River and State Water Project supplies and desalinated seawater from the Carlsbad plant. Rainbow, by contrast, imports all of its water through Metropolitan's Skinner plant in Temecula.

If you are on City of Oceanside water, Fallbrook Public Utility District, San Dieguito or Olivenhain in Encinitas, Elsinore Valley in Wildomar, or one of the four districts that split Murrieta, we have not confirmed a hardness number for your supply. Oceanside, for example, blends imported water from the San Diego County Water Authority with Mission Basin groundwater that is desalted by reverse osmosis, so the only reliable figure is the one in the City's annual water quality report. Every utility publishes one, and the hardness line is usually in the table of secondary or general constituents. Your water bill names your supplier, which matters in places like Fallbrook and Encinitas where the agency can change from one street to the next.

What does hard water do inside a house?

The minerals stay dissolved in cold water and come out of solution when water is heated or evaporates. That is why the damage concentrates in a few places.

Tank water heaters

Scale settles to the bottom of the tank as sediment. On a gas heater that layer sits between the burner and the water, so you hear popping or rumbling as water trapped under it boils. On an electric heater, scale coats the lower element. Either way, the heater works harder for the same hot water. Flushing the tank periodically removes loose sediment; if it has hardened, flushing may not help much. When a heater is noisy, slow to recover, or leaking at the base, a water heater repair visit can tell you whether it is worth fixing, and our guide on repairing versus replacing a heater covers the cost math.

Tankless units

A tankless heater pushes water through a narrow heat exchanger at high temperature, which is exactly where scale builds fastest. Most manufacturers call for periodic descaling, and on very hard water that schedule is not optional. If you are weighing a switch, the tankless versus tank comparison explains why water treatment belongs in that decision.

Faucets, showers and appliances

White crust on aerators and showerheads, spotty glassware, and stiff single-handle valves are the everyday signs. Scale inside cartridges is a common reason a shower valve becomes hard to turn or will not hold a steady temperature, which is a job for shower valve repair rather than a new trim kit. Clogged aerators also explain many cases of weak flow at one fixture; if the whole house is affected, see the guide to low water pressure instead.

Should you install a water softener?

There is no single right answer. It depends on how hard your water actually is, how much the scale bothers you, and how much maintenance you are willing to do. Here are the common options with national cost ranges from Angi's water softener guide (the page does not state a data year):

Angi puts the average installation at about $1,500, with ongoing salt at roughly $5 to $10 per 40-pound bag, or $50 to $70 for potassium chloride.

Some practical points before you buy:

• Test first. A Vista Irrigation District customer could be anywhere in a wide range. A test kit at the kitchen tap, read alongside the district report, keeps you from sizing a softener for the wrong number.
• Plan the location. A whole-house softener needs a spot on the main line after the hose bibs you want to leave hard, plus a drain and usually an outlet. In many slab-on-grade homes that means the garage, where the main often enters.
• Know your disinfectant. Rainbow, Vista Irrigation District and San Clemente all disinfect with chloramines. If you add filtration, tell the installer so the media is chosen for chloramine rather than plain chlorine.
• Keep a drinking tap. Some households leave the kitchen cold line unsoftened or add a point-of-use filter there.

An independent plumber who handles softener installation in Oceanside can check the main line, the drain options and the loop if your house was built with one. The same work is available for homes on Vista Irrigation District water through Vista softener installers, for Rainbow customers around Bonsall, and in San Clemente.

If you skip a softener, what maintenance helps?

• Flush the tank water heater on the schedule in its manual, and more often if you hear sediment.
• Descale tankless units as the manufacturer directs.
• Soak aerators and showerheads in white vinegar a few times a year.
• Replace a scaled cartridge rather than forcing a stiff handle, which can break the stem.
• Watch the water heater's temperature and pressure relief valve; a valve crusted with mineral deposits should be looked at by a plumber.

Does replacing a scaled-up water heater need a permit?

Usually, yes. The City of Oceanside issues permits for like-for-like and tankless water heater replacements through its eTRAKiT system, and the City of Temecula requires a building permit for every water heater installation or replacement, including seismic bracing and relief valve requirements. If hard water has finished off your heater in the Temecula Valley, a Temecula water heater replacement should include that permit in the quote. Swapping a tank for a tankless unit can add gas, venting and electrical requirements, so ask about them up front.

When is scale a plumbing problem rather than a nuisance?

Call a plumber when a heater leaks or makes loud noise, when hot water runs out much sooner than it used to, when a valve will not shut off fully, or when a relief valve drips. Those are signs that minerals have moved past cosmetic spotting and into parts that control water and heat. A one-time visit to check the heater, the main shutoff and the fixtures can also tell you whether treatment is worth the money in your house.