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Bidet attachment warm water: your four options

A plain bidet attachment sprays cold water, because it's fed by the same cold line that fills your toilet tank. You can get warm water two ways: a "dual temperature" attachment with a second hose to the hot water pipe under a nearby sink (no plug needed), or an electric bidet seat that heats the water itself (needs an outlet).

Which one works for you comes down to two questions: is there a sink within a few feet of your toilet, and is there an outlet you can reach? This page goes through all four options, how to hook up the hot line, and how to make peace with cold water if neither fits. Fair warning: ASSJET is a cold-water attachment, so we have no reason to oversell warm.

The four ways to get warm (or not) water

Choosing between these? Our guides to choosing a bidet attachment for your toilet and the non-electric bidet attachment cover the rest of the decision. There's no fifth option that heats water with no sink line and no plug. If a product page says "warm water, no electricity", look closer: it is running a hose from your sink's hot pipe.

How a no-plug warm water attachment works

A dual-temperature attachment has two inlets instead of one. The cold inlet connects to the toilet with a T-adapter, exactly like a cold-only model. The hot inlet connects with a second hose to the hot water valve under your bathroom sink. A second knob on the attachment mixes the two, so you choose how warm it is.

No heater is involved. The warm water comes from your home's water heater, the same water that comes out of the sink's hot tap. So it's only as warm as your hot tap, and only after the hot water has reached the sink.

Check the distance before you buy

The hot hose has to run from the sink's hot valve to the attachment, along the floor or wall, without being stretched or pinched. Brands put a limit on it; one well-known US brand says its warm model needs the toilet within about 6 feet of the sink. Measure it this way:

1. Open the cabinet under the sink. Find the two valves on the wall. In US homes the hot one is usually on the left.
2. Run a tape measure from the hot valve, out of the cabinet, along the floor or baseboard, to the back of the toilet seat on the right side.
3. Add a foot for slack and for going around the cabinet's edge.
4. Compare that with the hot hose length the product lists. If it's short, don't count on stretching it.

A pedestal sink with no cabinet works the same way, the hose just shows more. A sink on the far side of the room, or in another room, usually rules this option out.

Hooking up the hot line, step by step

1. Turn off the sink's hot valve (clockwise) and open the hot tap to let the pressure out.
2. Unscrew the sink's hot supply hose from the valve. Keep a towel and a small bowl under it.
3. Screw the hot-side T-adapter (in the kit) onto the valve, then the sink's hose onto the T. Bathroom sink valves in the US are usually 3/8 inch compression; check your kit matches.
4. Run the hot hose from the T's side outlet to the attachment's hot inlet. Keep it away from where feet and the cabinet door will crush it.
5. Open the valve slowly and do the paper-towel leak test on each joint. Our install guide has the full leak test, and the T-valve leak guide covers drips at a T.

The cold side goes on exactly as in a normal install. If you've done one, this is the same job twice.

Why the warm water takes a while to come

When you open the hot tap at your sink, the first water out is cold: it's the water that was sitting in the pipe. The same happens at the bidet, plus the length of the bidet's hot hose. How long you wait depends on how far your sink is from the water heater.

• Warm it up first: run the sink's hot tap for a few seconds before you sit down. The hot water is then already at the sink.
• Or start on cold and turn the mix to warm as it comes through.
• Homes with a recirculating pump get hot water at the tap almost at once, so the bidet does too.

Warm water and scalding: set it before you sit

Your hot tap can be hotter than you'd ever want on skin there. The US Consumer Product Safety Commission recommends setting home water heaters to 120°F (about 49°C) to cut the risk of scald burns. Many heaters are set higher than that out of the box.

• Test the spray with your hand every time before you sit, until you know where the mix knob lives.
• Start on the cold side of the mix and turn toward warm, not the other way.
• If children or anyone who can't react fast uses the toilet, consider a cold-only model or check the heater's setting.
• If the water heater is set high, the electric seat route (which heats to a set temperature) or cold-only may be safer for your home.

Electric bidet seats: warm water, plus a plug

An electric seat replaces your toilet seat. It takes cold water from the tank line and heats it, either in a small tank inside the seat or instantly as it flows. Most also heat the seat, and many add a dryer and a nightlight.

The outlet question

It needs a power outlet near the toilet, on the side the cord comes out. Measure from the seat to the nearest outlet: cords are often short. Makers generally tell you not to use an extension cord. Bathroom outlets in US homes are required to have ground-fault protection (GFCI, the outlet with the test and reset buttons) under the national electrical code. If there's no outlet in reach, adding one is a job for an electrician, and a renter will need the landlord's yes.

Instant versus tank heating

• Tank seats keep a small amount of water warm. Long rinses can run cool at the end, and the tank uses some power all day to stay warm.
• Instant (tankless) seats heat as the water flows, so they don't run out. They usually cost more.

Fit

A seat has to match your bowl: round or elongated. Attachments don't care much; seats do. Our fit guide shows how to measure.

No sink near, no outlet: what then?

This is a lot of small bathrooms and most rentals. Your choices are:

1. Cold water, with the tips below. Most people stop noticing after a week or two.
2. A travel or squeeze bottle you fill with warm water at any tap. Cheap, works anywhere, a bit of a faff.
3. A handheld sprayer with a mixing valve, if a plumber can bring a hot line to the toilet. Bigger job, not renter-friendly.

How cold is "cold", and how to make it easier

A non-electric attachment sprays the same water as your cold tap. In summer that's mild; in a northern winter it's sharp. A few things help:

• Start low. A gentle spray feels less cold than a strong one. Turn it up once you're used to it.
• Use the first second. The water sitting in the bidet's hose is room temperature, so the very start of the spray is the mildest part.
• Short bursts rather than one long rinse.
• Give it a week. The "cold!" shock is mostly surprise. Once you expect it, it fades.

There's also the comedy value. Half the first-time reaction videos online are the cold water, and our bathroom god quiz has a result for people who'd rather laugh about it than heat it.

So, do you need warm water?

Cold-only has one more thing going for it: fewer parts, fewer joints, fewer places to drip. A second T and a second hose double the joints that can leak. If you're weighing the whole idea, our pages on bidet vs toilet paper and whether attachments are worth it help.

FAQ

Can a non-electric bidet have warm water?

Yes, if it connects to the hot pipe under a nearby sink. It uses your water heater's water; nothing in the attachment heats it.

Is there a warm water bidet with no sink and no electricity?

Not one that heats water itself. Without a sink line or a plug, your warm option is a bottle you fill with warm water.

How far can the toilet be from the sink?

It depends on the hot hose in the kit. One major brand says about 6 feet. Measure along the floor, not in a straight line.

Does a warm water bidet use more energy?

A sink-fed attachment uses a little hot water from your heater per rinse. An electric seat uses power to heat; a tank seat also uses some power all day to keep its water warm.

Is ASSJET warm water?

No. ASSJET is cold water only: one knob, no plug, no second hose. We'd rather say it here than have you find out in January.

Want the silly version of this decision? Take the bathroom god quiz. More answers in our bidet guides.

Sources

1. Avoiding Tap Water Scalds (set water heaters to 120°F), US Consumer Product Safety Commission. https://www.cpsc.gov/s3fs-public/5098.pdf
2. Do All Bidets Require Electricity?, Bio Bidet. https://biobidet.com/blogs/news/do-all-bidets-need-electricity
3. TUSHY Spa warm water bidet (toilet within about 6 feet of the sink), TUSHY. https://hellotushy.com/products/warm-water-bidet-tushy-spa
4. PureSpa dual temperature bidet attachment (sink hot supply hookup), Brondell. https://brondell.com/purespa-dual-temperature-bidet-attachment
5. National Electrical Code 210.8: GFCI protection for dwelling bathroom receptacles, NFPA 70. https://www.nfpa.org/codes-and-standards/nfpa-70-standard-development/70