Cloudy glasses out of the dishwasher. Dry, itchy skin after a shower. Laundry that feels stiff no matter how much detergent you use. Often, these kinds of everyday frustrations have the same underlying cause: high TDS in your water.
TDS, or Total Dissolved Solids, measures the amount of minerals and other substances dissolved in your water. High readings often mean elevated levels of calcium and magnesium, the same hard water minerals that cause scale buildup and wear down appliances. Not all high TDS water is hard water, but hard water is one of the most common reasons homeowners see high TDS numbers.
That’s why it helps to know how high TDS can show up in daily life—from your morning coffee to your evening bath—so you can spot the signs and understand what’s really going on.
Is high TDS water safe to drink?
When you see a high TDS reading, the first question is usually: Does that mean my water is unsafe? Short answer: not necessarily. Total dissolved solids refers to the overall amount, but doesn’t tell you exactly what those substances are.
The EPA recommends keeping TDS under 500 parts per million (ppm) for the best taste and quality. Once levels rise beyond 500 ppm, there’s a greater chance of potentially harmful contaminants that can make water unsuitable for drinking.
High TDS is most noticeable in drinking water, because it can make water taste salty, bitter, or metallic (sometimes with a faint odor) and affect everyday enjoyment:
- Coffee and tea - When TDS levels are high, your morning cup can taste flat or dull.
- Ice - Cloudy cubes that melt quickly are often the result of minerals and impurities trapped as water freezes.
- Cooking - Pasta, vegetables, and baked goods can be tougher or less flavorful when prepared with high TDS water.
In most U.S. households, high TDS is more of a quality concern than a health hazard. Because this depends heavily on what’s dissolved in the water, experts recommend testing to know what’s behind your TDS number.
What high TDS does to pets & plants
High TDS water can also affect plants and animals in your home. Dogs and cats have more sensitive taste and smell than we do, so changes in water quality may be more noticeable to them.
Fish and other aquatic pets are especially sensitive. Elevated TDS can cloud aquarium water, and when levels drift outside the range a species is adapted to, it stresses their bodies and can shorten their lifespan.
For plants, watering with high TDS water allows dissolved salts to build up in the soil. Over time, these minerals can alter pH, damage roots, block nutrient absorption, and create imbalances that make it harder for plants to thrive.
How high TDS affects your skin
While not unsafe to bathe in, high TDS water can make a big difference in how your skin feels.
High mineral levels can strip your skin’s natural oils and disrupt moisture balance, which is why showers with hard water often leave skin feeling dry, itchy, or tight.
If you already struggle with sensitive skin or conditions like eczema, high TDS can make flare-ups worse by irritating the skin barrier, making redness and inflammation more likely.
Because soap doesn’t lather or rinse as well in high TDS water, it can leave a filmy residue that can clog pores, dull your complexion, and even make skincare products less effective since they don’t absorb properly through the buildup.
High TDS and your hair
High TDS water can leave hair feeling heavy, rough, or dry. Minerals like calcium and magnesium cling to strands, creating buildup that blocks moisture and makes hair harder to manage.
If you color your hair, the same mineral buildup can cause it to fade faster and look less vibrant.
Because shampoo doesn’t lather or rinse as well in high TDS water, residue is more likely to stick around. That buildup can leave hair looking dull, cause scalp itchiness, and lead to more breakage. While high TDS doesn’t directly cause hair loss, the dryness and damage it creates can make hair look thinner over time.
Does high TDS make laundry worse?
High TDS water can make washing your clothes less effective and more frustrating. Minerals like calcium and magnesium accumulate on fabric fibers, making clothes scratchy. Dark colors can fade faster, while light fabrics start to look grayish or dingy over time.
Because these minerals interfere with detergent, you may need to use more of it. Even then, stains can be harder to remove. Residue from the water and detergent can linger in fabrics, sometimes causing odors or skin irritation.
It’s not just your clothes that take the hit from high TDS. Washing machines also collect mineral buildup, known as limescale, which coats the drum, pipes, and heating element. Over time, this reduces efficiency, drives up energy use, and can shorten its lifespan.
Why high TDS water leaves spots on dishes
If your glasses or silverware come out of the dishwasher looking cloudy, high TDS is usually the reason. As water dries, minerals like calcium and magnesium are left behind, leaving white spots or streaks on dishes and glassware.
The effects aren’t just cosmetic. The same mineral deposits also build up inside the dishwasher, coating spray arms, filters, and heating elements, forcing the machine to work harder and less effectively.
High TDS in showers, baths & pools
High TDS water is one of the main reasons bathrooms and pools are so hard to keep clean. As water evaporates, minerals like calcium and magnesium are left behind. In the bathroom, that shows up as limescale on showerheads, faucets, and tiles, plus soap scum that’s harder to scrub away. Over time, buildup can reduce water pressure and damage fixtures.
In pools and hot tubs, high TDS can make water cloudy and leave mineral deposits on walls, jets, and heaters. Elevated TDS also makes chlorine and other sanitizers less effective, so you’ll use more chemicals and still struggle to keep water balanced.
How high TDS damages appliances & plumbing
High TDS can also take a toll on the plumbing hidden in your walls. Over time, minerals collect inside pipes, narrowing water flow and putting extra pressure on joints. This can reduce water pressure at the tap and increase the risk of leaks. Faucets, fridge dispensers, and other fixtures may wear out faster with gradual mineral buildup.
For water heaters, including tankless systems, scale acts like insulation on heating elements, making the unit work harder to produce hot water and hurting efficiency.
Boilers and combi-boilers are especially sensitive to high TDS, and excess minerals in feedwater can cause foaming, carryover, and corrosion.
The higher the TDS in your home’s water, the harder your appliances and plumbing have to work. That means greater energy costs, more frequent maintenance, and a shorter service life.
Fixing high TDS in your home
If you’re dealing with high TDS water, you’ve probably come across a range of suggested fixes. Some methods, like boiling water or using basic carbon filters, don’t actually reduce dissolved minerals. Reverse osmosis (RO) systems are highly effective at reducing TDS, but whole-home RO setups can be expensive, complex to maintain, and waste significant amounts of water, which makes them impractical for most households.
A simpler, more practical alternative is Navien’s WEC, a whole-house water treatment system. Installed at the water entry point, WEC helps reduce TDS and hardness minerals while also improving taste, clarity, and odor. That means every tap, shower, and appliance gets cleaner water without the drawbacks of large-scale RO. WEC is eco-friendly, low-maintenance, and designed to deliver optimized water quality for bathing, laundry, dishes, and even your plumbing.
Discover our WEC Series: a saltless, tankless water treatment system, or learn more about measuring TDS levels in your water, and where dissolved solids come from.
