Hard water in Coto de Caza, CA

Tap water hardness
158mg/L
9.2gpg
Hard

Reported by Santa Margarita Water District · October 2025

CA typical
121 mg/L
EPA health violations since 2016
0
Softener for 3 people
24k grain
Data
Utility report

Tap water in Coto de Caza has about 158 mg/L of hardness, which is 9.2 grains per gallon. On the USGS scale that counts as hard. The number comes from Santa Margarita Water District, dated October 2025.

Coto de Caza on the hardness scale, with nearby cities
060120180240300360+CA typical 121Laguna Woods: 108 mg/LLaguna Woods 108Laguna Niguel: 151 mg/LLaguna Niguel 151Rancho Santa Margarita: 157 mg/LRancho Santa Margarita 157Las Flores: 158 mg/LLas Flores 158Ladera Ranch: 158 mg/LLadera Ranch 158Rancho Mission Viejo: 158 mg/LRancho Mission Viejo 158San Juan Capistrano: 158 mg/LSan Juan Capistrano 158Mission Viejo: 159 mg/LMission Viejo 159Laguna Hills: 160 mg/LLaguna Hills 160Aliso Viejo: 160 mg/LAliso Viejo 160Coto de Caza 158mg/L as calcium carbonate060120180240300360+CA 121Rancho Santa Margarita: 157 mg/LRancho San. 157Las Flores: 158 mg/LLas Flores 158Ladera Ranch: 158 mg/LLadera Ran. 158Rancho Mission Viejo: 158 mg/LRancho Mis. 158Mission Viejo: 159 mg/LMission Vi. 159Laguna Hills: 160 mg/LLaguna Hil. 160158 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

Coto de Caza sits 37 mg/L above the typical California figure of 121. Of the 10 nearest cities we track, 3 have softer water and 3 have harder. The range nearby runs from 108 mg/L in Laguna Woods to 160 in Laguna Hills.

What 158 mg/L means at home

Expect white crust on faucets and showerheads, plus spots on dishes that come out of the dishwasher.

Kettles collect scale quickly. Water heaters build up sediment at the bottom of the tank, which makes them work harder over time.

Soap and detergent need a little more to lather, and soap scum shows up in the tub.

Hardness is not a health problem, and EPA sets no limit for it. It is a matter of scale and soap.

What to do about it

At 158 mg/L most of the trouble is scale, and only a few things deal with it.

Ion-exchange water softener

The standard whole-house fix. It swaps calcium and magnesium for sodium or potassium and needs salt plus a drain. Size it with the calculator below.

Salt-free conditioner

No salt and no drain line. It changes how minerals form scale instead of removing them, so water still tests hard.

Reverse osmosis or carbon filter

Under-sink reverse osmosis removes minerals from drinking water only. Plain carbon filters improve taste but do not soften.

Softener size for Coto de Caza

3 people × 75 gallons a day × 9.2 gpg = 2,079 grains a day. A 24,000-grain unit regenerates about every 11 days.

Size it for your household

EPA record for Coto de Caza's water system

Santa Margarita Water District · PWSID CA3010101

No health-based violations since 2016

Serves about 165,275 people from surface water.

Health-based
0
Monitoring or reporting
0
Open now
0

TapWaterData ties Coto de Caza to this system. EPA's service-area records do not name Coto de Caza, so check the utility printed on your water bill.

Health-based means a contaminant above its legal limit or a missed treatment step. Monitoring and reporting violations are late or missing tests and notices. Source: EPA ECHO, 2026Q3 export, violations with periods starting 2016 or later. Full EPA record.

Questions

Is Coto de Caza water hard?

Yes. It measures about 158 mg/L (9.2 grains per gallon), which the USGS classes as hard.

What is the water hardness in Coto de Caza in grains per gallon?

About 9.2 gpg. One grain per gallon equals 17.1 mg/L, so 158 mg/L divided by 17.1 gives 9.2.

What size water softener do I need in Coto de Caza?

For 3 people using 75 gallons each per day, 9.2 gpg works out to about 2,079 grains a day. A 24,000-grain softener covers that with a regeneration about every 11 days.

Has the Coto de Caza water system had EPA violations?

EPA records show no health-based violations for Santa Margarita Water District since 2016.

Nearby cities

All 515 cities in California

Hardness data: TapWaterData US Water Hardness (utility report, October 7, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.