Laboratory Water Still For Distilled Water

Quick Answer: A laboratory water still is an apparatus that boils tap water and condenses the steam to produce distilled water for preparing solutions, rinsing glassware and other laboratory uses. Dissolved salts and other non-volatile impurities are left behind in the boiler.

Distilled Water from Tap Water

Tap water carries dissolved calcium, magnesium and sodium salts, chloride and traces of other substances that interfere with analysis, leave spots on glassware and give false results in tests for chloride or hardness. A water still removes them by the simplest route: the water is boiled by an electric heater, the steam rises away from the dissolved solids, and a water-cooled condenser turns it back into liquid, which runs out into a collecting bottle.

In many designs the cooling water leaving the condenser also feeds the boiler, already warmed, which saves water and keeps the level constant, and some stills switch the heater off if the supply fails. The listing does not state whether this still is all-glass or metal-bodied, its output per hour, its heater rating or its safety features, so those need to be confirmed. Volatile impurities such as dissolved carbon dioxide and some organics can distil over with the steam; for demanding analytical work, double distillation or further purification is used.

Distilled water keeps its quality longest in a clean, closed container such as a plastic carboy, from which wash bottles are refilled for rinsing.

Specifications

Function	Produces distilled water by boiling and condensing tap water
Removes	Dissolved salts and other non-volatile impurities
Services needed	Electrical supply, running cold water, drain
Water quality (general)	Suitable for general laboratory use; volatile impurities may carry over
Construction, output and heater rating	Confirm at enquiry

Applications

Supplying distilled water for reagents, standard solutions and dilutions in school and college labs
Final rinsing of glassware after washing, to avoid mineral spots
Filling autoclaves and water baths, where tap water would leave scale
Preparing water for microbiological media and biology practicals

Care & Handling

Turn on the cooling water before the heater, and never let the boiler run dry.
Descale the boiler and heater regularly; hard tap water leaves a crust that slows output and can damage the element.
Discard the first portion of distillate after cleaning or a long idle period.
Keep electrical parts dry, follow the unit’s operating instructions and unplug it before cleaning.

Why Choose LabEquip

Schools, colleges and small testing labs that need a steady supply of distilled water on site often install a laboratory water still instead of buying bottled water. LabEquip supplies stills within its chemistry lab equipment; confirm construction and output on the contact page.

Frequently Asked Questions

How is distilled water different from deionised water?

Distillation removes dissolved salts and non-volatile impurities by boiling and condensing, and also removes most microbes. Deionisation removes ions with exchange resins but leaves uncharged organics and microbes. Many laboratories use one or both, depending on the test.

Why does the still need running cold water?

The condenser must remove the heat carried by the steam. Without a steady flow of cooling water, steam escapes uncondensed and output falls; in designs where the same water feeds the boiler, the boiler level also drops.

How often should the still be descaled?

It depends on the hardness of the local tap water. Inspect the boiler and heater regularly, and remove scale with a mild descaling acid such as dilute citric or acetic acid when a crust appears, rinsing thoroughly afterwards.

Why does the distillate sometimes test slightly acidic?

Carbon dioxide from the air or the feed water dissolves in freshly distilled water, forming a little carbonic acid, so its pH is often below 7. Boiling it briefly and letting it cool in a closed vessel removes most of the dissolved gas when neutral water is needed.

Is distilled water from a still pure enough for all analyses?

It is suitable for most general laboratory work. Trace analysis, HPLC and some molecular biology work need higher-purity water produced by double distillation or further purification systems.

How should distilled water be stored?

In a clean, closed container, ideally the same one each time, away from fumes. Open containers absorb carbon dioxide and ammonia from laboratory air, and dirty containers reintroduce the impurities the still removed.

Last Updated: September 2026