How hard is the water in Rio del Mar, CA?

Tap water hardness
98mg/L
5.8gpg
Moderately hard

Reported by Soquel Creek Water District · September 2025

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

The water in Rio del Mar carries roughly 98 mg/L of dissolved calcium and magnesium, or 5.8 grains per gallon. That is moderately hard water. The number comes from Soquel Creek Water District, dated September 2025.

Rio del Mar on the hardness scale, with nearby cities
060120180240300360+CA typical 121Aptos: 98 mg/LAptos 98Gilroy: 113 mg/LGilroy 113Capitola: 132 mg/LCapitola 132Soquel: 132 mg/LSoquel 132Pleasure Point: 132 mg/LPleasure Point 132Live Oak: 147 mg/LLive Oak 147Santa Cruz: 147 mg/LSanta Cruz 147Scotts Valley: 148 mg/LScotts Valley 148Watsonville: 215 mg/LWatsonville 215Interlaken: 215 mg/LInterlaken 215Rio del Mar 98mg/L as calcium carbonate060120180240300360+CA 121Aptos: 98 mg/LAptos 98Capitola: 132 mg/LCapitola 132Soquel: 132 mg/LSoquel 132Pleasure Point: 132 mg/LPleasure P. 132Live Oak: 147 mg/LLive Oak 147Watsonville: 215 mg/LWatsonville 21598 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

Rio del Mar sits 23 mg/L below the typical California figure of 121. None of the 10 nearest cities we track has softer water. The range nearby runs from 98 mg/L in Aptos to 215 in Watsonville.

What 98 mg/L means at home

You may see faint white spots on glasses and shower doors after the water dries.

Scale builds up slowly. A kettle or coffee maker needs descaling now and then, maybe every few months.

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

Optional. Plenty of households at this level live with it and descale the kettle now and then.

Water softener

Worth a look if spots on glass bother you, or if your tankless water heater manual asks for softer water.

Carbon filter

Improves taste and removes chlorine. It leaves calcium and magnesium in place.

Softener size for Rio del Mar

3 people × 75 gallons a day × 5.8 gpg = 1,294 grains a day. A 24,000-grain unit regenerates about every 18 days.

Size it for your household

EPA record for Rio del Mar's water system

Soquel Creek Water District · PWSID CA4410017

No health-based violations since 2016

Serves about 40,962 people from surface water.

Health-based
0
Monitoring or reporting
0
Open now
0

TapWaterData ties Rio del Mar to this system. EPA's service-area records do not name Rio del Mar, 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 Rio del Mar water hard?

Somewhat. It measures about 98 mg/L (5.8 grains per gallon), which the USGS classes as moderately hard.

What is the water hardness in Rio del Mar in grains per gallon?

About 5.8 gpg. One grain per gallon equals 17.1 mg/L, so 98 mg/L divided by 17.1 gives 5.8.

What size water softener do I need in Rio del Mar?

For 3 people using 75 gallons each per day, 5.8 gpg works out to about 1,294 grains a day. A 24,000-grain softener covers that with a regeneration about every 18 days.

Has the Rio del Mar water system had EPA violations?

EPA records show no health-based violations for Soquel Creek Water District since 2016.

Nearby cities

All 515 cities in California

Hardness data: TapWaterData US Water Hardness (utility report, September 15, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.