Research editor: Nicholas Bauer, Founder & Research Editor · Updated November 2, 2026
Hot or cold water? The short answer
There is no single rule for every countertop dishwasher. HAVA R01 does not need added hot water; HAVA R09 advises against hot tank filling or a hot-water hookup. Faucet-fed models such as COMFEE CDC22P2AWW and Danby DDW631SDB specify hot inlet water. Match the exact model and filling method before connecting or pouring.
You fill a tank
Read the tank-fill instructions. A heated wash cycle is not a request to pour hot water into the reservoir.
You connect a faucet
Read the inlet-temperature specification and hookup steps. An internal heater does not cancel those requirements.
Find your model’s water-supply instructions
Choose the model and the filling method separately. Inlet temperature is the temperature entering the machine; a hot wash or rinse temperature is what happens later in the cycle.
| US model / supply | Tank filling | Faucet supply & source |
|---|---|---|
| HAVA R01 | Hot water is not needed. The machine heats water for the selected wash cycle. | HAVA R01 Q&A confirms automatic heating. Follow the exact unit’s filling and hose instructions. |
| HAVA R09 | HAVA advises against adding hot water directly. Its heating pump heats water during the cycle, except Fruit. | HAVA R09 Q&A also advises against connecting to a hot-water faucet. This is not a hot-supply model. |
| COMFEE CDC17P2AWW | Manual filling is supported. For the Fruit cycle, the manual specifically requires manually added cold water, not automatic faucet filling. | Manual, pp. 1, 16 and 25: optional faucet installation tells you to open the hot-water line. It does not give a numeric inlet target in that connection step; do not substitute the CDC22 specification. |
| COMFEE CDC22P2AWW | Faucet-fed model; no manual-fill tank. | Manual, technical information, printed p. 19: hot-water connection should be 120°F (about 49°C). |
| BLACK+DECKER BCD6W | Faucet-fed model; no manual-fill tank. | Support manual, pp. 8–10: hot-water connection; the specification gives 120° without a unit. Confirm the unit with support rather than assuming °F or °C. |
| Danby DDW631SDB | Faucet-fed model; no manual-fill tank. | Owner’s manual, p. 2: inlet 120–149°F (48–65°C, as printed). The product FAQ’s discussion of heating cold water does not override this installation range. |
These are model-specific source summaries, not a universal installation temperature. Match your rating label and supplied manual. A revised model or regional version can have different requirements.
Do not pour boiling water into a tank
A high-temperature wash claim is not permission to preheat the fill water to that temperature. Use the maker’s filling instructions. Likewise, a tank-filled machine still needs its drain hose routed and secured correctly.
Do countertop dishwashers heat their own water?
Many do, but wash temperature and inlet temperature are different. The inlet is the water entering the appliance. The wash or final rinse temperature describes what happens inside during a program.
That explains why a machine can have an internal heater and still specify a hot-water connection. For example, the CDC22 manual lists a 120°F inlet, while the R01 product guidance says you do not need to add hot water. Neither statement establishes the rule for another model.
Do not use a high-temperature wash claim on a product listing as a tank-fill target. The table above links the installation evidence so you can check the distinction yourself.
What does “167°F cleaning” mean for the water you add?
A product headline can describe a different stage from the inlet or main wash. We checked HAVA’s current cycle tables against its filling answers on November 2, 2026:
| Exact model and program | Published cycle table | Filling decision |
|---|---|---|
| R01 — Normal | 131°F wash; 154°F rinse | HAVA says added hot water is unnecessary. These cycle temperatures are not tank-fill targets. |
| R09 — Normal | 131°F wash; 167°F rinse | HAVA advises against hot tank filling and a hot faucet supply. |
The R09 page also uses “167°F” in its cleaning promotion. Its detailed Normal-cycle table identifies that number as the rinse temperature. Use the installation and filling instructions for the incoming water; use the cycle table to understand the selected program. These are published specifications, not temperatures we have independently measured.
Resolve a conflicting instruction before connecting
Save a short record instead of combining advice from two similar-looking models. This is especially useful when a retailer listing, product FAQ and supplied manual disagree.
- Identity: full model code, country version and manual revision or publication date.
- Method: manual tank filling or the supplied faucet connection.
- Program: normal dishwashing or a program with a special fill instruction.
- Exact instruction: the inlet-temperature number, its unit and the page or section where it appears. Leave an omitted unit unresolved.
Message to the manufacturer: “I have [model and region], using [tank/faucet] and [program]. My manual [revision/page] says [instruction], but your listing says [other instruction]. Which incoming-water requirement applies to this unit, and can you send the matching installation instructions?”
Keep the answer with the manual. Do not treat a wash or rinse temperature as an installation requirement, or raise a household water-heater setting to match an ambiguous number.
Can you use a countertop dishwasher with cold water only?
Choose a model whose instructions support your available supply. If you want to avoid relying on a hot-water faucet, the R01’s manufacturer guidance is relevant. The R09 also advises against a hot-water supply. Check the exact version before buying.
For a model that specifies hot inlet water, cold water is not an approved substitute merely because the appliance also contains a heater. We have not established equivalent cleaning results or cycle times under an unsupported hookup.
A manual-fill option removes the faucet connection from the filling routine, but it still needs a suitable drain route, power outlet and stable placement. See tank vs faucet countertop dishwashers for the everyday tradeoffs.
Three checks before the first wash
- Match the complete model number. CDC17 and CDC22 are different machines. Use the label on your unit and the manual supplied with it, including the regional version.
- Find the supply instruction. Check “water connection,” “installation” or “technical information,” then check whether a particular program changes the filling method.
- Confirm your kitchen can supply it. For a faucet-fed machine, verify the water requirement and approved faucet connection. Follow the manual’s connection, shutoff and pressure-release sequence.
If documents conflict, give the manufacturer your model number and manual revision and ask which inlet condition applies. Do not change the household water-heater setting to satisfy a guessed requirement.
Hot and cold water questions
Do I turn on the hot tap or the cold tap?
Use the exact model’s hookup instructions. The CDC17 optional faucet procedure calls for the hot-water line, while HAVA advises against a hot faucet for the R09. The machine’s small size does not settle the choice.
Can I put boiling water into a dishwasher tank?
Do not use boiling water as a shortcut. A hot wash rating describes the cycle, not permission to pour boiling water into a tank. Follow the manufacturer’s fill instructions.
Does a tank dishwasher need a hot-water connection?
Not necessarily. HAVA R01 says hot water is not needed. Check each tank model separately, including any program-specific filling rule.
Will cold inlet water make a hot-supply model take longer?
Do not assume a longer cycle makes an unsupported supply acceptable. We have not tested that substitution. Follow the inlet requirement instead of predicting performance from the presence of a heater.
Are these rules the same for a built-in dishwasher?
This page covers the six countertop models listed above. For a built-in or full-size portable dishwasher, use that appliance’s installation manual; do not copy a countertop tank-fill rule.
Choose the setup your kitchen can support
Once the water supply is settled, compare capacity, cabinet clearance and the daily filling routine.
- Compare six countertop dishwashers by setup and fit
- HAVA R01 vs COMFEE CDC17P2AWW — two manual-fill options with different details.
- Work through the countertop dishwasher setup checklist
- Watch Miles explain countertop dishwasher setup
Sources and scope
Manufacturer documentation checked October 23, 2026. This guide interprets installation information; it is not a hands-on temperature or cleaning test. The six model rows link to their sources.
- HAVA R01 and R09: manufacturer product Q&A on heating and filling.
- COMFEE CDC17P2AWW: printed pp. 1, 16 and 25. CDC22P2AWW: technical information, printed p. 19 (PDF page 21).
- BLACK+DECKER BCD6W: printed pp. 8–10. The specification prints “120°” without a unit; the hookup instructions identify the hot-water line.
- Danby DDW631WDB/DDW631SDB: September 2021 owner’s manual, printed p. 2. Its stated inlet range takes precedence over a general discussion of internal heating.
Need a correction? Send the model and manual revision so we can check the relevant instruction.
