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City water profile

San Diego water quality

Compare local ZIP estimates, evidence quality, associated public systems, and compliance history for San Diego, California.

Median indexed hardness

729PPM

43 indexed ZIPs

Range 182–728.5 PPM

State comparison
540 PPM above
State hardness rank
#1 of 242
Matched utilities
1
Active health records
0

City summary

What the indexed records say

San Diego has 43 published ZIP profiles across San Diego County. The indexed median is 729 PPM, compared with 189 PPM across California.

Among the 242 Californiacities with an indexed median, San Diego ranks #1from highest to lowest. Across all 678 state ZIP profiles, available estimates run from 3.3to 728.5 PPM.

The 182–728.5 PPM range shows how much the available ZIP estimates vary within the city label. At least one estimate is marked low confidence, so observation distance and date deserve extra attention.

Hardness distribution

How local ZIP estimates compare

Soft0 ZIPs
Moderately hard0 ZIPs
Hard0 ZIPs
Very hard43 ZIPs

43 of 43 ZIP profiles have a hardness estimate. Bars count ZIP profiles, not households or laboratory samples.

Evidence quality

Distance, dates, and confidence

Median nearest distance
43.8 miles
Profiles with evidence
43/43

Confidence labels

High: 0Moderate: 0Low: 43

Observation window: Jan 7, 2016 to May 14, 2026.

ZIP directory

Water reports in San Diego

Open a ZIP for site-level provenance and measurements.

ZIP code

92014

Very Hard

490.5 PPM

Nearest site
30.8 mi
Confidence
Low

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ZIP code

92037

Very Hard

715 PPM

Nearest site
38.3 mi
Confidence
Low

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ZIP code

92092

Very Hard

715 PPM

Nearest site
36.8 mi
Confidence
Low

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ZIP code

92093

Very Hard

715 PPM

Nearest site
36.4 mi
Confidence
Low

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ZIP code

92101

Very Hard

728.5 PPM

Nearest site
47.6 mi
Confidence
Low

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ZIP code

92102

Very Hard

728.5 PPM

Nearest site
47.9 mi
Confidence
Low

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ZIP code

92103

Very Hard

728.5 PPM

Nearest site
45.6 mi
Confidence
Low

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ZIP code

92104

Very Hard

728.5 PPM

Nearest site
46.1 mi
Confidence
Low

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ZIP code

92105

Very Hard

728.5 PPM

Nearest site
46.4 mi
Confidence
Low

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ZIP code

92106

Very Hard

728.5 PPM

Nearest site
48.3 mi
Confidence
Low

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ZIP code

92107

Very Hard

728.5 PPM

Nearest site
46.3 mi
Confidence
Low

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ZIP code

92108

Very Hard

728.5 PPM

Nearest site
43.8 mi
Confidence
Low

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ZIP code

92109

Very Hard

728.5 PPM

Nearest site
42.9 mi
Confidence
Low

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ZIP code

92110

Very Hard

728.5 PPM

Nearest site
44.4 mi
Confidence
Low

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ZIP code

92111

Very Hard

728.5 PPM

Nearest site
41.5 mi
Confidence
Low

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ZIP code

92113

Very Hard

728.5 PPM

Nearest site
49.4 mi
Confidence
Low

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ZIP code

92114

Very Hard

728.5 PPM

Nearest site
48.9 mi
Confidence
Low

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ZIP code

92115

Very Hard

728.5 PPM

Nearest site
45.1 mi
Confidence
Low

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ZIP code

92116

Very Hard

728.5 PPM

Nearest site
44.5 mi
Confidence
Low

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ZIP code

92117

Very Hard

728.5 PPM

Nearest site
40.2 mi
Confidence
Low

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ZIP code

92119

Very Hard

715 PPM

Nearest site
41.6 mi
Confidence
Low

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ZIP code

92120

Very Hard

728.5 PPM

Nearest site
42.8 mi
Confidence
Low

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ZIP code

92121

Very Hard

490.5 PPM

Nearest site
35.2 mi
Confidence
Low

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ZIP code

92122

Very Hard

728.5 PPM

Nearest site
38 mi
Confidence
Low

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ZIP code

92123

Very Hard

728.5 PPM

Nearest site
41.4 mi
Confidence
Low

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ZIP code

92124

Very Hard

715 PPM

Nearest site
40.4 mi
Confidence
Low

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ZIP code

92126

Very Hard

490.5 PPM

Nearest site
34.3 mi
Confidence
Low

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ZIP code

92127

Very Hard

182 PPM

Nearest site
27 mi
Confidence
Low

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ZIP code

92128

Very Hard

182 PPM

Nearest site
29 mi
Confidence
Low

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ZIP code

92129

Very Hard

303 PPM

Nearest site
30.8 mi
Confidence
Low

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ZIP code

92130

Very Hard

490.5 PPM

Nearest site
31.8 mi
Confidence
Low

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ZIP code

92131

Very Hard

678 PPM

Nearest site
35.9 mi
Confidence
Low

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ZIP code

92132

Very Hard

728.5 PPM

Nearest site
47.9 mi
Confidence
Low

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ZIP code

92134

Very Hard

728.5 PPM

Nearest site
47.2 mi
Confidence
Low

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ZIP code

92136

Very Hard

728.5 PPM

Nearest site
50.1 mi
Confidence
Low

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ZIP code

92139

Very Hard

728.5 PPM

Nearest site
50.8 mi
Confidence
Low

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ZIP code

92140

Very Hard

728.5 PPM

Nearest site
46 mi
Confidence
Low

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ZIP code

92145

Very Hard

678 PPM

Nearest site
37.3 mi
Confidence
Low

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ZIP code

92147

Very Hard

728.5 PPM

Nearest site
47.2 mi
Confidence
Low

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ZIP code

92154

Very Hard

728.5 PPM

Nearest site
58.6 mi
Confidence
Low

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ZIP code

92161

Very Hard

715 PPM

Nearest site
36.9 mi
Confidence
Low

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ZIP code

92173

Very Hard

728.5 PPM

Nearest site
59.3 mi
Confidence
Low

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ZIP code

92182

Very Hard

728.5 PPM

Nearest site
44.1 mi
Confidence
Low

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Public water systems

Utilities associated with this city

San Diego, City Of

PWSID CA3710020

Surface water
System population served
1,385,379
Last reported
Jun 22, 2026

The system names this served city; Census place overlap links the city to this ZCTA.

Compliance history

What EPA records show

No active health-based violation appears among the associated systems in the represented EPA reporting quarter. This does not mean every contaminant was tested at every tap.

No violation records are included in the current lookback window.

Practical next steps

Move from index to evidence

  1. 1. Open your ZIP. Check distance, dates, confidence, and the associated utility.
  2. 2. Read the current CCR. Confirm source water, detections, limits, ranges, and notices.
  3. 3. Test the tap when needed. Confirm health concerns or treatment sizing with the right method.

Questions people ask

About water in San Diego

Is the water hard?

The indexed city median is 729 PPM. Open the ZIP report to verify the distance and confidence behind that estimate.

Is the tap water safe?

Compliance history is utility-wide and cannot guarantee conditions at every tap. Check current notices and test when address-specific evidence is needed.

Do I need treatment?

Choose treatment only after confirming the problem at the property. A softener targets hardness; contaminant treatment requires a matching, verified performance claim.