It is the classic rented-flat problem: the kitchen has no free water connection, or the landlord does not allow a conversion, and yet the dishes pile up every evening. That is exactly what tank dishwashers are for: mini dishwashers with a built-in 5 litre water tank that only need a 230 V socket. In our mini dishwasher comparison we reviewed three of them.
The key points in brief
- Does a dishwasher really work entirely without a water connection? Yes. Tank dishwashers have an integrated 5-litre water tank that is filled from above with a jug or measuring cup.
- How much water and electricity does a tank dishwasher use per wash cycle? All three tank dishwashers reviewed need 5.0 litres per wash cycle (Heinrich's in Eco programme 4.5 L).
- How much crockery fits in a mini dishwasher with a tank? All three tank models hold 2 place settings according to the IEC standard, which is the crockery of about two people for one meal.
Details and reasoning in the article, FAQ at the end
How does a dishwasher without a water connection work?
The principle is simple: at the top of the appliance sits a 5-litre water tank that is filled with a jug or measuring cup before the wash cycle; tap water is enough. The appliance heats the water itself, washes like a large machine in several cycles and pumps the dirty water out through a supplied hose: into the sink, a bucket or straight into a drain, as you prefer.
Two of the three reviewed models are hybrids: the MEDION DWT20 and the Heinrich's HTG 8841 can be run either from the tank or the classic way via a fixed water connection. The Bomann TSG 5701 is the tank classic with the same dual option and a start delay of up to 24 hours, handy for off-peak electricity tariffs.
The water calculation: 5 litres instead of 40 to 60
The often overlooked point: a tank dishwasher saves a huge amount of water compared with washing by hand. When washing by hand, 40 to 60 litres run through the tap, depending on habit. All three tank dishwashers, by contrast, need 5.0 litres per wash cycle (the Heinrich's in the Eco programme only 4.5 L).
Electricity also stays manageable: between 0.314 kWh (MEDION in the Eco programme, the thriftiest) and 0.40 kWh (Bomann, Eco) per cycle. At 35 cents per kilowatt-hour (German electricity price) that is 11 to 14 cents of electricity plus about 2 cents of cold water: a complete wash cycle costs under 20 cents. If you wash up daily, that comes to about €50 to €60 a year, water included.
Three tank dishwashers in a direct comparison
| Model | Connection | Place settings | Power (Eco) | Programmes | Price | Score |
|---|---|---|---|---|---|---|
| Bomann TSG 5701 | Tank or mains water | 2 | 0.40 kWh | 5 (incl. glass) | from €370 | 8,6/10 |
| MEDION DWT20 | Tank or mains water | 2 | 0.314 kWh | 6 (incl. baby care) | from €230 | 8,5/10 |
| Heinrich's HTG 8841 | Tank or mains water | 2 | 0.38 kWh | 6 (incl. fruit mode) | from €249 | 7,9/10 |
In short: the MEDION DWT20 is the most economical at 0.314 kWh per cycle and at from €230 also the cheapest, plus it has a baby care programme with a higher temperature for baby bottles. The Bomann TSG 5701 scores with a stainless steel interior, Aquastop and the most solid build, but costs the most. The Heinrich's HTG 8841 is the oddball with a fruit mode (washing fruit and vegetables); in rating and drying it falls somewhat behind the other two.
When a fixed water connection is the better choice after all
The 2 place settings of the tank dishwashers correspond to the crockery of about two people per meal. If you regularly cook for more people, or simply want to wash up less often, you hit the limit. Then it is worth a look at the Klarstein Amazonia 6: a countertop dishwasher with 6 place settings and 49 dB, which however requires a mains water connection (inlet hose with Aquastop included). At from €272 it sits in price between the tank models.
The rule of thumb: no connection or maximum flexibility → tank. Connection available and 2+ people → mains-water countertop dishwasher. The hybrid models from MEDION and Heinrich's leave both options open, for example first as a tank appliance in a rented flat, later permanently connected in the new kitchen.
Who a tank dishwasher is worth it for
- Tenants without a free connection: the core scenario. A socket is enough, no conversion, no conversation with the landlord.
- Office kitchenettes: colleagues' cups and plates without blocking the sink.
- Campers, motorhomes, tiny homes: 230 V from shore power is enough; details in the camping vs. household guide.
- 1 to 2 person households: 2 place settings fit the daily load; more in the guide Appliances for the single household.
The limits, honestly stated
There are three things to know before buying. First: 2 place settings are not many, as large pots and pans over 28 cm do not fit, and plates only up to about 25 cm in diameter. Second: the energy efficiency classes look off-putting (D to G), but that is down to the EU scale, which is tailored to 60 cm appliances; in absolute terms 0.31 to 0.40 kWh per wash cycle is economical. Third: the tank needs filling; if you find that annoying every day, take one of the hybrid models and connect it as soon as a connection is available.
Frequently asked questions
Does a dishwasher really work entirely without a water connection?
Yes. Tank dishwashers have an integrated 5-litre water tank that is filled from above with a jug or measuring cup. The waste water runs through a hose into the sink or a bucket. Only a 230 V socket is needed, which is why these appliances work in rented flats without a connection, in office kitchenettes and even in a motorhome.
How much water and electricity does a tank dishwasher use per wash cycle?
All three tank dishwashers reviewed need 5.0 litres per wash cycle (Heinrich's in Eco programme 4.5 L). Electricity use ranges from 0.314 kWh (MEDION DWT20, Eco) to 0.40 kWh (Bomann TSG 5701, Eco). At 35 cents per kWh (German electricity price), a wash cycle therefore costs around 11 to 14 cents of electricity plus about 2 cents of cold water, under 20 cents in total.
How much crockery fits in a mini dishwasher with a tank?
All three tank models hold 2 place settings according to the IEC standard, which is the crockery of about two people for one meal. Plates fit up to a diameter of around 25 cm, large pots and pans over 28 cm do not. For a 1 to 2 person household, that is plenty with a daily wash cycle.
Tank dishwasher or fixed water connection: which is better?
The tank is the right choice if there is no connection or the appliance needs to be placed flexibly (rental, office, camping). If a connection is available and more than one person is washing up, the step up to a mains-water countertop dishwasher such as the Klarstein Amazonia 6 with 6 place settings is worthwhile. MEDION DWT20 and Heinrich's HTG 8841 can do both, by the way: tank or mains water.
Verdict
A dishwasher without a water connection is not a compromise purchase but, for rented flats, offices and mobile households, often the only practical solution, and at under 20 cents per wash cycle a surprisingly cheap one. The value-for-money recommendation is the MEDION DWT20 (lowest consumption, from €230); if you value build quality, go for the Bomann TSG 5701. All details and alternatives are in the big mini dishwasher comparison.