ZIP Code 94520
Contra Costa County, California — Concord
What This Means
Contra Costa County, California has hard water, estimated at 170 mg/L (PPM). Hard water causes noticeable mineral scale on faucets, showerheads, and inside water heaters. You may notice spots on dishes, stiff laundry, and dry skin or hair. A water softener is recommended to protect your plumbing and appliances.
What You Should Do
Hardness Details
| ZIP Code | 94520 |
| County | Contra Costa |
| City | Concord |
| State | California (CA) |
| Hardness (PPM) | 170 mg/L — Hard |
| Hardness (GPG) | 9.9 grains/gallon |
| Classification | 121 - 180 mg/L |
Source: USGS Water Quality Portal, county-level median
Your Water Utility
| Utility Name | CONTRA COSTA WATER DISTRICT |
| System ID | CA0710003 |
| Water Source | Surface water |
ⓘ Your utility may treat water before delivery, which can change hardness levels. Check your utility's annual Consumer Confidence Report (CCR) for exact hardness values.
USGS Monitoring Data
| Monitoring Stations | 99 |
| Range | 20 – 2910 mg/L |
| Most Recent Data | 2022 |
| Data Quality | Measured |
Source: USGS Water Quality Portal
Effects at 170 PPM Hardness
At 170 ppm, expect noticeable effects: soap scum buildup on fixtures and shower doors, cloudy spots on dishes, dry skin and hair after bathing, and reduced water heater efficiency. Laundry may feel stiff, and you will likely need more detergent for effective cleaning.
Is Concord Water Safe to Drink?
Yes. Hard water at 170 ppm in Concord is safe to drink. The calcium and magnesium that make water hard are actually essential minerals your body needs daily. The World Health Organization confirms there are no health-based guidelines for water hardness.
You may notice a slightly mineral or chalky taste at this hardness level. A drinking water filter (pitcher-style carbon filter or under-sink reverse osmosis system) can improve taste if desired, though the water remains perfectly safe to drink unfiltered.
Your Water vs National Average
Concord water at 170 ppm is 70% harder than the US average of approximately 100 ppm. This means your area has harder water than most of the country, and a water softener would provide more benefit here than in an average American home.
Best Solution for 170 PPM Water
A whole-house water softener is recommended ($800–2,500 installed). At 170 ppm, an ion exchange softener will protect your water heater, dishwasher, and plumbing from scale buildup. You will also notice improved skin and hair health, softer laundry, and reduced soap and detergent usage. The system typically pays for itself within 3–5 years through energy savings and extended appliance life.
Contra Costa County Water Hardness Map
Soft Moderate Hard Very Hard
Check Another ZIP Code
Nearby ZIP Codes
Frequently Asked Questions
What is the water hardness for ZIP code 94520?
ZIP code 94520 is in Contra Costa County, California, with estimated water hardness of 170 mg/L (9.9 GPG), classified as hard. The area is served by CONTRA COSTA WATER DISTRICT.
Do I need a water softener in 94520?
With hard water at 170 PPM, a water softener is recommended to protect your plumbing and appliances from mineral scale buildup.
What county is ZIP code 94520 in?
ZIP code 94520 is in Contra Costa County, California (CA).
Is Concord water hard or soft?
Concord water is classified as hard with an estimated hardness of 170 ppm (9.9 GPG). This is hard water — you may notice scale buildup, dry skin, and spots on dishes.
Is hard water in 94520 safe to drink?
Yes, hard water in ZIP code 94520 at 170 ppm is safe to drink. The calcium and magnesium minerals are actually beneficial for your health. You may notice a slightly mineral taste. A simple carbon or reverse osmosis filter can improve taste if desired, but the water is perfectly safe unfiltered.
Will 170 PPM water damage my appliances?
At 170 ppm (hard), scale buildup will reduce water heater efficiency and can shorten appliance lifespan. A water softener is recommended to protect your investment.
Do I need a water softener in Contra Costa County?
Yes — Contra Costa County has hard water at 170 ppm. A water softener ($800-2,500 installed) is recommended to protect plumbing and appliances.
Is Concord water OK for aquariums and plants?
Use caution. At 170 ppm, soft-water fish species may struggle. Consider using filtered water for aquariums. For plants, hard water can raise soil pH — use rainwater or filtered water for acid-loving species.