Distilled water is useful to aquarium keepers, plant growers and DIY skincare makers for one reason: it starts with almost nothing dissolved in it, so you control what goes in. That is also its limit. Fish and plants usually need minerals or nutrients added back, and distilled water is pure, not sterile, so homemade cosmetics still need good hygiene and a suitable preservative.
Below we look at each hobby in turn: what tap water can do in each one, where distilled water helps, and the mistakes people make when they first switch.
Why do hobbyists want a “blank slate” water?
Tap water is made safe for people to drink. To get there it may carry dissolved minerals (hardness), a disinfectant such as chlorine or chloramine, and other trace substances that are harmless to us at regulated levels. Fish, sensitive plants and some homemade cosmetics can react to the same water differently.
Distillation boils water, leaves dissolved solids behind in the boiling chamber and condenses the steam. University of Nebraska–Lincoln Extension lists hardness minerals, sodium, iron, nitrate, chlorine and chloramines among the substances distillation removes. Some volatile compounds can travel with the steam, which is why Megahome distillers pass the condensed water through an activated-carbon post-filter. Owners of Megahome distillers report TDS meter readings of about 0–6 ppm on their distilled water. That is the “blank slate”.
Is distilled water good for aquariums?
Yes, as a starting point, but rarely on its own. Here is how keepers use it.
The tap-water problem: chloramine
Many water utilities disinfect with chloramine instead of free chlorine. A fish-keepers' guide from the City of Sioux Falls water plant explains why that matters. Chloramine makes water safe to drink but is toxic to fish, reptiles and amphibians, because fish take water in through their gills and the chemical reaches their blood directly. Unlike chlorine, chloramine does not disappear if you let a bucket stand for a day. The guide says boiling does not remove it, and most reverse osmosis membranes let it pass. Breaking chloramine down also releases ammonia, which has to be dealt with too.
Where distilled water helps
- Top-ups for marine and reef tanks. When water evaporates the salt stays in the tank, so keepers top up with fresh, low-mineral water to keep salinity steady instead of adding more minerals.
- Soft-water species. Some fish and shrimp come from very soft water. Starting from distilled water lets you build exactly the hardness they need instead of fighting hard tap water.
- Predictable water changes. If your tap water changes with the season, a consistent base makes your test readings easier to interpret.
Remineralise and test before use
Pure water has almost no buffering capacity, so its pH can swing easily, and most fish need some dissolved minerals. Keepers usually add an aquarium remineraliser or salt mix until they reach the hardness and pH their species need. Two habits are worth keeping:
- Test a sample with a total chlorine kit and an ammonia kit before your first batch goes into a tank. The Sioux Falls guide warns that a free-chlorine test can read zero on chloraminated water that is still toxic to fish. Ammonia can evaporate with the steam, so check rather than assume.
- Change the carbon post-filter on schedule. Megahome's manual says each sachet should be replaced within 25 days, and sooner if the water tastes or smells odd.
For a sick or unusual animal, ask an aquatic vet or an experienced specialist store before changing its water.
Should you water plants with distilled water?
Most garden and house plants do fine with ordinary tap water or rainwater. Distilled water earns its place with plants that are sensitive to dissolved salts, or when you want precise control over nutrients.
Orchids
The American Orchid Society notes that rain reaching wild orchids carries only about 10–25 ppm of total dissolved solids, and that hard water can give plants a dull appearance. It calls reverse osmosis the most common purification method among orchid growers and distilled water “the purest possible”. Its warning: pure water has no buffering capacity, so even a little of most standard fertilisers can make the solution too acidic. Use a fertiliser formulated for pure water, or adjust it. The same article warns against salt-based softened water, which it says can be toxic to plants.
Carnivorous plants
Venus flytraps, sundews and pitcher plants evolved in nutrient-poor bogs. Growers widely recommend rain, distilled or reverse osmosis water for them, because the minerals in hard tap water can build up in their peat-based media. Unlike orchids, they are usually not fertilised through the water at all.
Hydroponics and seedlings
In hydroponics, the nutrient solution is the plant's food. Starting from very low-TDS water means your meter shows what you added, not what was already in the tap water. This makes dosing and troubleshooting simpler.
Is distilled water better for DIY skincare?
It is a sensible base, but it is not a safety step on its own.
- Why makers use it: with few dissolved minerals, distilled water is less likely to react with other ingredients or leave residue, and every batch starts the same.
- What it does not do: distilled water is pure, not sterile. Once it touches a jar, a spoon or your fingers, microbes can get in. FDA's guidance on cosmetics lists contaminated water and ineffective preservation among the ways products become contaminated, and notes that microbial contamination is a common reason for cosmetic recalls. In its manufacturing checklist, FDA expects professional makers to test both their ingredient water and how well a finished product's preservation holds up.
Practical hygiene for home makers:
- Use freshly distilled water collected in a clean, closed container.
- Sanitise jars, tools and work surfaces, and wash your hands.
- Treat any water-containing recipe as needing a preservative system suited to it, or make tiny batches and use them quickly.
- Store products as your recipe instructs, and throw them out if the smell, colour or texture changes.
Distilled water does not give skincare any special effect. It simply removes one variable from your recipe.
Making your own distilled water at home: what to expect
Hobbyists often get through more distilled water than a household drinks. Home distillation saves repeated trips for bottled distilled water, which has at times been hard to find in some US stores. It helps to know what daily life with a countertop distiller looks like:
| Item | Megahome MH-943TWS family |
|---|---|
| Batch size | 4 L |
| Time per batch | about 5.5–6 hours |
| Rated power | 580 W (about 0.8 kWh per litre, estimated) |
| Water path | Stainless-steel boiling chamber and steam dome, activated-carbon post-filter, glass or PP bottle |
Owners are honest about the trade-offs. The fan is audible, a batch takes most of a morning, and the unit warms the room it is in. The most common cause of trouble is scale baked onto the boiling chamber, so descale with citric acid at least once a month, more often with hard water. The unit switches itself off when a batch is done, and there is no need for an external timer. The CDC also notes that bacteria can grow on a distiller's cooling coils when the unit sits unused, so after a pause, run a batch and discard it before using the water for a tank or a recipe.
Megahome has made distillers in Tainan, Taiwan, since 1992. Its US listings have close to 5,000 Amazon ratings, averaging 4.5–4.7★ as of September 2026, and owners often mention taste and low TDS readings. You can compare models on the MH-943TWS page and find local sellers on Where to buy. For the science of each step, see How does a water distiller work?. To see how distilled water compares with reverse osmosis for low-TDS water, read Distilled vs reverse osmosis vs spring water.
Key takeaways
- Distilled water is a low-mineral starting point. It is most useful when you want to control what is dissolved in the water.
- Aquariums: chloramine in tap water must be dealt with for fish. Distilled water helps for top-ups and soft-water species, but usually needs remineralising, and the first batches should be tested for total chlorine and ammonia.
- Plants: orchids, carnivorous plants and hydroponics benefit most. Use fertilisers suited to pure water, and avoid salt-softened water.
- Skincare: distilled water is pure, not sterile. Hygiene and preservation still decide how safe a homemade product stays.
- A home distiller makes 4 L per batch. Descale regularly and change the carbon sachet on schedule.
Frequently asked questions
Can I put distilled water straight into my fish tank?
Not on its own for most freshwater tanks. It lacks the minerals and buffering fish need, so keepers add a remineraliser or salt mix to reach their species' target hardness and pH. Plain distilled water is mainly used to top up evaporation in marine tanks. Follow the advice of your aquatic vet or specialist store for your animals.
Does boiling tap water make it safe for fish?
Not if your supply uses chloramine. Utility guidance for fish keepers says boiling and letting water stand do not remove it. Use a conditioner that treats chloramine and ammonia, or high-quality activated carbon, and test with a total-chlorine kit.
Is distilled water good for orchids?
It can be. The American Orchid Society describes distilled water as the purest option and RO as the most common choice among growers. Because pure water has no buffering, use a fertiliser designed for pure water so the solution does not become too acidic.
Does distilled water stop homemade skincare from spoiling?
No. It is pure but not sterile, and any water-based product can grow microbes once opened. Clean tools, a suitable preservative system or very small batches, and proper storage are what keep a homemade product usable.
How much distilled water can a home distiller make?
A Megahome countertop distiller makes 4 L per batch in about 5.5–6 hours, so one or two batches a day covers most aquarium top-ups, plant watering and recipe needs.
Sources
- City of Sioux Falls – Chloramines and Fish
- American Orchid Society – Water Your Orchids
- University of Nebraska–Lincoln Extension – Drinking Water Treatment: Distillation (G1493)
- US CDC – About Home Water Treatment Systems
- US FDA – Microbiological Safety and Cosmetics
- US FDA – Good Manufacturing Practice Guidelines/Inspection Checklist for Cosmetics
- Amazon.com – Megahome countertop water distiller listing (ratings)
- Rocky Mountain Water Distillers – Distilled water shortage
