The best water distiller | Automatic fill 12 gallon distiller

best water distiller
best water distiller

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Finding the best water distiller that can produce pure and soft drinking water for a big family is a daunting task as most distillers on the market are just for families of not more than 3 people.

The Durastill 4640 water distiller is an automatic fill system with a capacity that can satisfy the needs of a big family of up to 8 people.

Unlike most water distillers out there, the Durastill 4640 requires little to no human input to perform its work. Once you connect the system to a water supply and electricity, it will distill and refill automatically, even when you are asleep.

About the manufacturer

Durastill is a family owned and operated business headquartered in the United States.

Founded by Paul Giovagnoli, the company began its operations in the mid-1970s, by then it was trading under the name International Rotor Company.

Durastill has become one of the most trusted brands in the United States and across the globe. Their distillers are widely used in the US military, US agencies and embassies dotted across the world.

The company is well known for producing the best water distiller systems which are rugged, dependable and simple for an average user.

With over 30 years’ experience under its belt, Durastill is the very best in regard to technical support. They have a well knowledgeable and robust sales and technical support network in the US and across the globe.

They have been selling this particular model for so may years. So you can expect it to function perfectly as it has been perfected over the years, fixing most technical issues associated with water distillers.

How Durastill 4640 water distiller works

There is no need to add water manually to the water distiller. Simply connect the water distiller to a water line for a continuous automatic operation all day long.

The distiller is simply plugged into a standard 115 volt outlet, so there is no need to engage an electrician.  

Fix the reservoir tank to the bottom of the distiller using the fittings provided with the purchase, as directed in the user manual/ installation guide.

After connecting the distiller to a water line and plugging it into a 115 volt outlet, it’s time to turn it on.

Also don’t forget to connect that cable that links the reservoir tank and the distiller itself. The link enables communication between the reservoir tank and the distiller.

best water distiller

Showing the connections between reservoir tank and distiller

The communication between the reservoir tank and water distiller ensures that the distiller turns off when the reservoir tank is full. This saves you electricity and makes sure that there are no water messes due to overfilling of the reservoir tank.

The water distiller automatically turns ON and OFF to replenish the reservoir tank with pure distilled water. So if you are away for some hours and the reservoir tank is full, the water distiller will switch itself off.

The way the system distills water follows the general principles and processes of water distillation which I explained in detail in this well detailed article.


  • Stainless steel parts ensures that the distiller and the reservoir tank last for decades
  • Can be plugged into a standard 115 volt power outlet.
  • Comes with pre-filter and post filter. Pre-filter is the one used to filter debris. The carbon post filter is the one that eliminates all VOCs like chloramine, chlorine, methanol and ethanol out of your pure distilled water.
  • The water distiller alone weighs 36 pounds(over 16KGs)  
  • The reservoir tank alone weighs 29 pounds (about 13 KGs).
  • So the combined weight of the water distiller plus the storage tank is about 68 pounds(30 kilograms or so)
  • The distiller dimensions are 13 inches or 33cm for the height;20 inches or ~50cm for the width and 13 inches or ~33cms for the depth
  • The reservoir tank dimensions are 29 inches or ~74 cm for the height; 20 inches or ~51 cm for the width and 13 inches or ~33cms for the depth.
  • The overall height of the unit (water distiller plus the reservoir tank) is 39 inches or approximately 100cm/1 meter
  • It has a 10 gallon reserve tank, enough for a big family.
  • The volatile gas vent ensures that all VOCs including chlorine are eliminated before condensation takes place.
Best metal water distiller so far


  • The caster wheels make it easy to move the unit around the house or office in spite of its relatively heavy weight.
  • The wattage of the unit is 1500 watts, a power consumption rate which is very good for its size. The total cost of making distilled water using this distiller translates to around 25 cents per gallon, in the United States.
  • It has a capacity of making 12 gallons or 46 liters of pure distilled water every 24 hours. The water is enough to provide clean drinking and cooking water for a family of about eight people.
  • It is an install and forget system. There is no need for manual filling of the distiller with water; it is done automatically per rising need.
  • The distiller switches itself ON when there is a need to replenish the storage tank with distilled water. So the distiller won’t use electricity when the reservoir tank is full.
  • It is manufactured in the USA, so getting the spare parts delivered to your doorstep is so easy; it is the best water distiller of this size if you live in the USA.
  • It is convenient.It comes with a faucet which is convenient and with a water level gauge
  • It has a self-sterilization feature. You don’t need to buy any special chemical or equipment to sterilize the reservoir tank, it is an inbuilt feature.
  • Can be converted easily.The distiller can be switched from auto-fill to manual-fill if the water supply is not that reliable. Just flip a switch on the distiller to convert the distiller to manual-fill.


  • 1 year guarantee. The guarantee covers the replacement of parts in case the parts stop working. Terms and conditions apply as always. You cannot just be careless with the distiller and expect a replacement.
  • Its heavy weight is offset by its mobility. It has caster wheels.
  • It is automatic, hands off machine. So it is the best water distiller of this size for a family with little time to operate this system manually.
  • Saves you a significant amount of money. It costs around 25 cents to produce a gallon of distilled water. Buying a gallon of distilled water in a grocery shop costs an average of $5. So we are talking of huge savings here.
  • It is the best water distiller of this size that comes with everything you need for a normal installation.
  • A float switch ensures that the distiller is automatically switched off when the boiler gets low. So it is completely safe to leave the water distiller unattended while it is running.
  • You can connect a remote faucet to provide pure water throughout the house; it is a convenient feature isn’t it!
  • Comes with easy to understand manuals and installation guides


  • It is bulky. However, the castor wheels make it easy to move the distiller around.


To sterilize the storage tank, simply flip the fan switch off for a while when steaming. This should be done while the tank is empty. For a more detailed explanation on how this and other maintenance works are done on the distiller, please check this guide.

Your reservoir tank will be sterile in a matter of minutes, full of pure uncontaminated drinking water.  

This is the best water distiller for someone who wants a huge capacity distiller with little to no maintenance costs.

Final verdict

The Durastill 4640 water distiller is an outstanding system that suits a big family. It has a staggering output rate of 12 gallons per day.

 The fact that it is made out of stainless steel makes it a durable asset that will provide your home with pure soft water for so many years to come.

The automatic fill capability is the greatest selling feature of the system.

Although it might appear expensive to fork out such a significant amount of money once off, it will prove to be cheap to maintain it in the long run. The self-sterilization feature makes it so easy and hustle free to maintain the system.

In spite of its heavy weight, the water distiller is very mobile as it comes with castor wheels.

In my opinion, this is the best water distiller you can buy for a family of more than 3 people, the capacity is just right for a medium to big sized families.

I regard this system as the best water distiller in its family of high capacity home distillers. I give this water distiller an overall star rating of 4.7.Generally the unit is very good,but you might need to seriously consider the price first before you commit to it.

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If you want see other smaller,functional and cheaper distiller ,check the Mini-Classic CT counter-top water distillation unit