ZIP Code 20670
St. Mary's County, Maryland — Patuxent River
What This Means
St. Mary's County, Maryland has naturally soft water, estimated at 29 mg/L (PPM). Soft water is generally good for appliances and plumbing — it produces less scale buildup. You likely don't need a water softener. Soft water may feel slightly "slippery" and lathers soap easily.
What You Should Do
Hardness Details
| ZIP Code | 20670 |
| County | St. Mary's |
| City | Patuxent River |
| State | Maryland (MD) |
| Hardness (PPM) | 29 mg/L — Soft |
| Hardness (GPG) | 1.7 grains/gallon |
| Classification | 0 - 60 mg/L |
Source: USGS Water Quality Portal, county-level median
Your Water Utility
| Utility Name | PATUXENT NAVAL AIR STATION (NAVFAC-WASH) |
| System ID | MD0180022 |
| Water Source | Ground 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 | 141 |
| Range | 1.2 – 3000 mg/L |
| Most Recent Data | 2022 |
| Data Quality | Measured |
Source: USGS Water Quality Portal
Effects at 29 PPM Hardness
At 29 ppm, your water is soft. You are unlikely to notice mineral effects on skin, hair, or appliances. Soap lathers easily, dishes come out spot-free, and your water heater and plumbing will not accumulate scale buildup.
Is Patuxent River Water Safe to Drink?
Yes. Hard water at 29 ppm in Patuxent River 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.
At this level, taste is generally good. Most people will not notice a mineral flavor, and the water is perfectly suitable for drinking, cooking, and making coffee or tea.
Your Water vs National Average
Patuxent River water at 29 ppm is 71% softer than the US average of approximately 100 ppm. Your area benefits from naturally soft water, which is gentler on plumbing, appliances, skin, and hair than what most Americans experience.
Best Solution for 29 PPM Water
No softener needed. Your soft water at 29 ppm is ideal for skin, hair, and appliances. You are in the fortunate minority of US homes that do not need water treatment for hardness. Enjoy the benefits of naturally soft water: easy soap lathering, spot-free dishes, and long-lasting appliances.
St. Mary's County Water Hardness Map
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Frequently Asked Questions
What is the water hardness for ZIP code 20670?
ZIP code 20670 is in St. Mary's County, Maryland, with estimated water hardness of 29 mg/L (1.7 GPG), classified as soft. The area is served by PATUXENT NAVAL AIR STATION (NAVFAC-WASH).
Do I need a water softener in 20670?
With soft water at 29 PPM, a water softener is generally not needed.
What county is ZIP code 20670 in?
ZIP code 20670 is in St. Mary's County, Maryland (MD).
Is Patuxent River water hard or soft?
Patuxent River water is classified as soft with an estimated hardness of 29 ppm (1.7 GPG). This is soft water — no treatment is needed.
Is hard water in 20670 safe to drink?
Yes, hard water in ZIP code 20670 at 29 ppm is safe to drink. The calcium and magnesium minerals are actually beneficial for your health. At this level, the water tastes normal and requires no filtration for drinking purposes.
Will 29 PPM water damage my appliances?
At 29 ppm (soft), your water will not cause mineral damage to appliances. You can expect full lifespan from your water heater, dishwasher, and plumbing.
Do I need a water softener in St. Mary's County?
No — St. Mary's County has soft water at 29 ppm. A water softener is not necessary.
Is Patuxent River water OK for aquariums and plants?
Yes — soft water at 29 ppm is ideal for most tropical fish (bettas, tetras, discus) and acid-loving plants. African cichlids may need mineral supplements.