Mandeville Water Hardness & Quality Report (2026)
Water Hardness
4.3 grains per gallon
Source
river
pH Level
7.5
neutral = 7.0
Lead
0.003 mg/L
✓ Below action level
TDS
136.8 mg/L
Est. Daily Cost
$0.20
energy & soap waste
Source: USGS Water Quality Portal · Updated 2026
0–60
mg/L
Soft
61–120
mg/L
Moderately Hard
121–180
mg/L
Hard
180+
mg/L
Very Hard
Appliance Damage Report
In Mandeville, your appliances are currently losing 10% efficiency due to mineral buildup.
| Appliance | In Mandeville | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 7.2 yrs | 8.5 yrs | -15% |
| Washing Machine | 10.9 yrs | 12 yrs | -9% |
| Water Heater | 12.6 yrs | 15 yrs | -16% |
Regional Water Comparison
How Mandeville compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Mandeville, Louisiana | 74 mg/L | 7.9 ppt | 🟡 Moderately Hard | river |
| Slidell, Louisiana | 154 mg/L | 13.2 ppt | 🟠 Hard | river |
| Metairie, Louisiana | 112 mg/L | 10.4 ppt | 🟡 Moderately Hard | river |
| Metairie Terrace, Louisiana | 112.5 mg/L | 10.4 ppt | 🟡 Moderately Hard | river |
| New Orleans, Louisiana | 74.5 mg/L | 7.9 ppt | 🟡 Moderately Hard | river |
National Benchmark
How Mandeville compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Mandeville | 74 mg/L | 🟡 Low |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
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What Makes Mandeville's Water Unique?
Local geology and source profile
Mandeville, Louisiana, in Saint Tammany Parish — a Saint Tammany Parish city adjacent to Covington and Slidell on the north shore of Lake Pontchartrain — receives its water from the St. Tammany Parish Water, drawing from the Bogue Falaya River or Bogue Chitto (Saint Tammany Parish) through the north Lake Pontchartrain distribution.
The soft 74 mg/L hardness and TDS of 136.8 mg/L reflect the north Louisiana Saint Tammany Parish Gulf Coast supply's soft character — the Miocene Catahoula Formation insoluble and Pleistocene Prairie Formation slightly calcareous produce soft water typical of the north Lake Pontchartrain communities (compare Abbeville LA: 69/124.5 in Vermilion Parish comparable; Minden LA: 84/150 in Webster Parish comparable; Mandeville similar soft Louisiana range). The Bogue Falaya watershed at Saint Tammany Parish — Miocene Catahoula Formation (insoluble — primary dilutant), Pleistocene Prairie Formation (slightly calcareous — primary hardness contributor), and Holocene Lake Pontchartrain alluvium (chloride — minor TDS).
At 74 mg/L, Mandeville's water is soft — scale forms very slowly in appliances, dishwashers remain efficient, and no softening is needed. Annual descaling is appropriate. The PFAS level of 7.9 ppt warrants a certified drinking water filter — the Saint Tammany Parish north Louisiana industrial and petrochemical corridor contribute to Mandeville's elevated readings.
Geology & Source: Mandeville in Saint Tammany Parish draws from the St. Tammany Parish Water on the Bogue Falaya River or Bogue Chitto (Saint Tammany Parish, north Lake Pontchartrain, Louisiana) — the Bogue Falaya watershed at Saint Tammany Parish drains Miocene Catahoula Formation (insoluble) and Pleistocene Prairie Formation (slightly calcareous) — Louisiana Saint Tammany Parish Bogue Falaya Miocene insoluble supply produces soft water at 74 mg/L with TDS 136.8 mg/L.