Portsmouth Water Is Soft

Why Is Portsmouth Water So Soft?

Portsmouth sits at 1.4 GPG (24 ppm), which puts it squarely in the soft category. That’s not an accident of treatment; it’s a function of where the water comes from and what it travels through before it reaches your tap. The city draws from surface water sources, and surface water in this part of Virginia simply doesn’t pick up much calcium or magnesium along the way.

Here’s the whole story. Rain falls, runs off the land, and collects in rivers and reservoirs rather than soaking deep into limestone or dolomite bedrock. Those underground formations are what load water up with hardness minerals. When water spends time in contact with calcium-rich rock, it dissolves the minerals and carries them along. Surface water doesn’t get that extended contact. It moves across the top of the ground, through soil and sandy coastal plain sediments, and into the intake. The geology of the Tidewater region is dominated by unconsolidated sands, silts, and clays, not by the carbonate rock that makes water hard. Those sandy deposits are chemically inert when it comes to hardness. They don’t contribute calcium or magnesium the way limestone aquifers do.

So the water arriving at Portsmouth’s treatment plant is already low in hardness minerals. Treatment doesn’t soften it; it’s just naturally soft to begin with. The result is water that measures 1.4 GPG, well below the USGS threshold of 7 GPG for “hard” and even further below the 10.5 GPG mark for “very hard.” For context, the USGS puts the national average around 7.3 GPG, so Portsmouth is running roughly five times softer than the typical American household. You’re not imagining it if your soap lathers easily and your shower doors stay clear. That’s soft water doing what soft water does.

The flip side is that soft water can be slightly more corrosive to metal pipes, which is part of why utilities in this region pay close attention to pH and alkalinity adjustments. But that’s a treatment concern, not a hardness problem. The hardness itself is genuinely low, and it stays that way year-round because the source doesn’t change character with the seasons the way some hard-water aquifers do.

How Portsmouth Compares to Nearby Cities

Portsmouth’s 1.4 GPG puts it on the soft end of the spectrum for the Hampton Roads area, but it’s not alone. The cities in this region largely draw from the same kind of surface water sources, so the hardness profile tends to run similar across municipal lines. Norfolk, Chesapeake, and Virginia Beach all pull from surface water reservoirs and rivers in the region, and their water reflects that same geology. None of them are wrestling with the kind of 10-plus GPG water you’d find in parts of the Midwest or Southwest where groundwater moves through limestone.

That said, there are real differences between the cities, and they come down to source specifics. Some neighboring systems blend water from multiple reservoirs or add groundwater to meet demand during dry spells. When a utility brings groundwater into the mix, even temporarily, hardness can tick up noticeably. Portsmouth’s supply stays consistently soft because it doesn’t rely on those groundwater supplements to the same degree. If you’ve noticed that water in one nearby city feels slightly different from another, that’s likely why. It’s not your imagination; it’s the difference between a straight surface water supply and a blended one.

The practical upshot is that Portsmouth residents rarely need to think about hardness. Scale buildup in water heaters is minimal, soap and detergent do their job with less product, and appliances tend to last longer. According to the WQA and Battelle’s 2010 detergent study, soft water can require up to 50% less laundry detergent and up to 70% less dish soap compared to hard water. The Battelle Memorial Institute and WQRF’s 2009 research also found roughly 4% gas water-heater efficiency loss per 5 GPG of hardness, which means Portsmouth’s soft water keeps heaters running close to their rated efficiency. The DOE notes that even a quarter-inch of scale can cause up to 40% efficiency loss, but at 1.4 GPG, you’re unlikely to see that kind of buildup in the first place. Hard water shortens water-heater service life by an estimated 30-50%, and at Portsmouth’s levels, you’re on the favorable end of that equation.

The one thing worth watching in Portsmouth isn’t hardness at all. The detected contaminants in the supply include disinfection byproducts like total trihalomethanes and haloacetic acids, plus chromium (hexavalent). Those are regulated under EPA standards, and hardness itself is not regulated as a health hazard. The EPA classifies it as aesthetic only, under the Secondary Maximum Contaminant Level. So the soft water is a genuine advantage for your plumbing and your laundry, but it doesn’t mean the water is free of everything else. Those byproduct levels are a separate conversation, and they’re driven by the disinfection process, not by the geology that makes the water soft.

How does Portsmouth stack up against the rest of Virginia? It's soft at 1.4 GPG — Alexandria, Richmond, and Hampton sit nearby with different numbers. See the full hardest-water ranking for context.

See where Portsmouth sits on the Virginia water hardness map →

Want the broader explainer on what hardness actually is and how it behaves? Read hard water vs. soft water, explained.