Water hardness in West Covina
9.7 gpg hard
Tap water in West Covina is hard: 9.7 gpg (166 mg/L · 9.3 °dH · 16.6 °fH).
Source: Walnut Valley Water District 2025 Consumer Confidence Report (2025) · data checked 2026-10-23
Range across supply zones: 97–280 mg/L.
2 supply zones — hardness varies by neighbourhood; the figure above is the median.
Hardness by district / supply zone
| gpg | mg/L | ||
|---|---|---|---|
| Walnut Valley WD portion: MWD Weymouth Treatment Plant water (~60% of WVWD supply) | 13.7 | 234 | very hard |
| Walnut Valley WD portion: TVMWD Miramar Treatment Plant water (~39% of WVWD supply) | 5.7 | 97 | moderately hard |
Walnut Valley Water District, which serves part of West Covina, buys imported water through Three Valleys and Metropolitan, treated at the Weymouth plant. That water combines Colorado River Aqueduct and State Water Project supply, and the share changes, so the 2 zones span 97 to 280 mg/L CaCO₃ with a median of 165.5 mg/L. Hard water, with scale on fixtures and in heaters.
USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
Water data
| Total hardness | 9.7 gpg |
|---|---|
| Utility | Walnut Valley Water District (serves a portion of West Covina) |
How West Covina compares
- Tap water in West Covina is 7 % harder than the median of the 1372 cities we track in the United States (9.1 gpg).
- By hardness it ranks 644 of 1372 in the United States (1 = hardest); 53 % of these cities have softer water.
- In California it is number 161 of 336 cities; the regional median is 9.5 gpg.
- Nearest city with clearly softer water: East Pasadena, 15 km away (5.2 gpg).
- Nearest city with clearly harder water: La Puente, 4 km away (13 gpg).
Ranking of the hardest and softest water in the United States →
What it means at home
- Fast scale on taps, shower screens and kettle; white spots on glassware.
- Water heater: efficiency loss and element failures within years if unprotected.
- Dry skin and dull hair after showering are common.
- Softener recommended; jug or reverse osmosis for drinking.
How much salt will you use for softening?
Recommended, especially with a heater or boiler: scale cuts efficiency and shortens its life.
Descale a coffee machine or kettle about every 2 months (typical manufacturer guidance for this hardness).
Estimates for planning, not a quote. Check your appliance manual for exact settings.
Dishwasher setting in West Covina
| Brand | Setting for this water |
|---|---|
| Bosch | H02 |
| Miele | 9 °dH |
| AEG / Electrolux | 2 |
| Beko | 3rd |
| Hoover | S1 |
| LG | H2 |
From each brand's manual for the model family named in the source; your model may differ, so check its manual. All brands and how to change the setting →
FAQ
Is West Covina water hard or soft?
It is hard: 166 mg/L as CaCO₃ (9.7 gpg, 9.3 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in West Covina safe to drink?
Hardness is not a health issue; it is about limescale, taste and appliances. Mains water must meet national drinking-water standards. USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
How many grains per gallon is West Covina water?
9.7 gpg, equal to 9.3 °dH, 16.6 °fH or 166 mg/L calcium carbonate.
What dishwasher salt setting should I use in West Covina?
For 166 mg/L (9.3 °dH) check your manufacturer's table: level 4–5.
Do I need a water softener in West Covina?
Recommended if you have a water heater, boiler or tankless unit: it saves repairs and detergent.
Source
Source: Walnut Valley Water District 2025 Consumer Confidence Report (2025). Method: figure published by the water supplier. Walnut Valley Water District 2025 Consumer Confidence Report · Outdated figure? Tell us