If you've come across the term "smart toilet" and found yourself wondering what it actually means in practice - how water gets where it needs to go, what happens when you press a button, and whether the whole thing is as complicated as it sounds - you're not alone. Smart toilets and bidet toilet seats are still relatively new to most UK households, and the gap between "I've heard of this" and "I understand how it works" is wider than it should be.
The good news is that once you understand the basic mechanism, a wash and dry toilet is a straightforward piece of technology. There are no mysterious processes involved; just a thoughtfully designed system that uses water and warm air to do what toilet paper has always done, but more effectively and with considerably more comfort. This guide explains exactly how it works, step by step, in plain English.
What Is a Wash and Dry Smart Toilet?
A wash and dry smart toilet (sometimes called a bidet toilet, a smart toilet seat, or a Japanese toilet) is a toilet that cleans the user with a warm water spray after use, then dries them with a warm air dryer. The result is a complete, hands-free toileting experience that requires no toilet paper and no physical reaching or wiping.
It comes in two main formats: a bidet toilet seat that attaches to your existing toilet pan in place of your current seat, and an all-in-one smart toilet unit that replaces the entire toilet. Both formats work on the same fundamental principles; the difference is in the form factor rather than the function.
Where Does the Water Come From?
This is the first question most people ask, and it has a simple answer. The Washloo connects to your existing cold mains water supply (the same supply that feeds your toilet cistern) via a T-piece connector fitted to the water inlet hose. No hot water supply is needed. The unit heats the water internally using a small reservoir heating tank, so the water that reaches you is warm, not cold.
The water is heated to a temperature you choose. On Washloo models, water temperature typically has four settings - low (around 33°C), medium (around 36°C), high (around 39°C) and off - so you can set it to whatever feels most comfortable for you. The unit remembers your settings between uses, so you don't need to adjust anything each time.
Because the water is drawn directly from the mains and heated within the unit itself, there is no need for a separate hot water connection, no tank in the loft to worry about, and no risk of running out of warm water mid-use.
How Does the Seat Know When Someone Is Sitting Down?
Built into every Washloo bidet seat is a body sensor, a small pressure or proximity sensor located in the seat itself. This sensor detects when someone is seated and activates the standby mode, making the wash functions available. When the seat is empty, the wash and dry functions are locked out, which prevents accidental activation and is a straightforward but important safety feature.
On models with an auto-opening lid, such as some of Washloo's all-in-one smart toilet units, the sensor also triggers the lid to open automatically as you approach, and close again once you move away. This hands-free operation is particularly valuable for people with limited dexterity or those who find bending and reaching difficult.
What Does the Wash Function Actually Do?
When you activate the wash function, a small nozzle extends from within the body of the bidet seat. This nozzle is retracted and hidden during normal toilet use (you won't notice it) and only emerges when the wash function is activated.
The nozzle delivers a controlled, pressurised stream of warm water at a position and angle that can be adjusted to suit the user. There are typically two wash modes:
Rear wash (posterior wash): The nozzle positions itself to clean the posterior area. This is the function used after a bowel movement.
Front wash (feminine wash / lady care): The nozzle moves to a forward position to clean the frontal area. This function is designed specifically for female users and is a separate, distinct wash mode from the rear wash.
On most Washloo models, both wash modes also offer an oscillating function; the nozzle moves gently back and forth during the wash cycle, providing wider, more thorough coverage than a fixed stream alone.
Adjusting the Wash
The wash is fully adjustable in real time. Using the remote control or the side control panel on the seat, the user can change:
Water pressure: typically three settings (low, medium and high), so the spray can be gentle or more powerful depending on preference and sensitivity.
Water temperature: four settings from low to high, adjustable at any point during the wash.
Nozzle position: the nozzle can be moved forward or backwards to find the exact right position for each user. This is particularly important for people of different body shapes and sizes, as well as those with positioning challenges due to mobility conditions.
All of these adjustments happen instantly and can be made as the wash is running.
How Does the Nozzle Stay Hygienic?
This is a concern many people raise, and it's a sensible one. The answer is that the nozzle on a Washloo is self-cleaning. Before and after every wash cycle, the nozzle automatically rinses itself with clean water. This means it enters and exits the wash cycle clean and is never in contact with the toilet bowl itself.
On Washloo models, the nozzle is also made from stainless steel or a nano-antibiotic plastic - a material engineered to inhibit bacterial build-up on the surface. Combined with the automatic self-clean cycle, this makes the nozzle one of the more hygienic parts of the entire toilet system.
On some models, the Washloo also includes a deodoriser - a built-in air purification function that activates automatically during use, drawing bathroom air through a filter to neutralise odours. This operates quietly and without any user input.
How Does the Drying Function Work?
Once the wash cycle is complete, the dryer function can be activated, either manually by pressing a button or automatically as part of the Auto/One Solution cycle (more on that below). A warm air dryer built into the rear of the bidet seat blows a gentle stream of warm air, similar in principle to a hand dryer, to dry the area after washing.
The dryer temperature is adjustable across four settings, from low to high, so it can be set to a comfortable level for each user. The drying cycle typically takes between 30 seconds and a few minutes, depending on the selected temperature and pressure.
For people with sensitive skin, reduced sensation, or conditions that require careful temperature management, including those living with diabetes, neurological conditions, or post-surgical sensitivity, the low setting provides effective drying without the risk of discomfort from heat.
What Is the Auto/One Solution Function?
The Auto function (also called the One Solution function on some Washloo models) is designed to make the entire process as effortless as possible with a single button press. When activated, the Washloo automatically cycles through the complete sequence: rear wash, oscillating wash, warm air dry and stop. The user doesn't need to select each function individually or remember any sequence of buttons.
This function is particularly valuable for people with cognitive conditions such as dementia, for those with limited dexterity who find pressing multiple buttons challenging, and for anyone who simply prefers a streamlined, one-touch experience. It's one of the features that makes the Washloo genuinely useful as an accessibility tool, not just a luxury add-on.
What Is the Heated Seat?
In addition to the wash and dry functions, most Washloo models include a heated toilet seat. The seat is heated to a temperature selected by the user (again, across multiple settings) and maintains that temperature while in use. After ten minutes of inactivity, the seat temperature reduces to a lower standby level to conserve energy, and returns to the set temperature when someone sits down again.
For people with conditions that cause muscle stiffness, joint pain or cold sensitivity - including arthritis, Raynaud's disease, or spinal injuries - a heated seat can make a meaningful practical difference to comfort in the bathroom, particularly first thing in the morning or during cold weather.
What About the Night Light?
Most Washloo models include a built-in LED night light that illuminates the toilet bowl and surrounding area with a soft glow. This is activated at the touch of a button and can be left on throughout the night. Its purpose is to allow safe navigation to and use of the toilet without needing to turn on a main bathroom light, which is important both for people who need to use the toilet at night (nocturia is a common symptom of several conditions) and for those sharing a home with others whose sleep they don't want to disturb.
For people living with dementia or visual impairment, the night light also helps with spatial orientation in the bathroom, making the toilet easier to locate and approach safely in low-light conditions.
How Does the All-in-One Smart Toilet Differ?
Washloo's all-in-one smart toilet units, such as the Prestige and Supreme, incorporate all of the above features into a complete toilet basin, with no separate cistern required. Instead of a traditional gravity-fed flush, these units use an internal water tank and an ultra-quiet pump to deliver a powerful flush using only around 2 to 2.5 litres of water - roughly half the volume of a standard UK toilet flush.
Flushing on the Prestige, for example, is triggered automatically when the user stands up and the seat sensor detects that they have left the seat. A manual foot button provides a backup flush option, and a battery backup ensures flushing remains available in the event of a power cut, something standard electric smart toilets cannot offer.
These units are cisternless, which makes them more compact and significantly sleeker in appearance. At around 58cm in length, the Prestige is notably smaller than most standard close-coupled toilets, making it suitable for bathrooms with limited space.
Frequently Asked Questions
Does a wash and dry toilet use a lot of water? No. The wash cycle uses a small, controlled amount of water; far less than the water used to produce the toilet paper it replaces. All-in-one Washloo units also use approximately half the water per flush compared to a standard toilet.
Is the water spray uncomfortable? Not if set correctly. The water temperature and pressure are both fully adjustable, and Washloo recommends starting on low settings for first-time use to find your comfort level before increasing. Most users find warm water cleansing considerably more comfortable than wiping with paper.
Can children use a wash and dry smart toilet? Yes. Washloo models include a Kids function, which reduces the water pressure and sets the temperature to a safe medium level, cycling through a gentler wash sequence at the touch of a button. The seat sensor is also adaptable to smaller users.
What happens if there is a power cut? On bidet toilet seat models, the wash and dry functions will not operate without power. However, the toilet can still be used and flushed normally via the cistern. On all-in-one units such as the Prestige, a battery backup maintains the flush function during a power cut.
Is a wash and dry smart toilet suitable for people with mobility difficulties? Yes, and this is one of its most significant benefits. The hands-free operation eliminates the need to reach, twist or wipe, which can be difficult or impossible for people with limited upper-limb mobility, joint pain, or post-surgical restrictions. The Auto/One Solution function makes the entire process manageable with a single button press, and remote control operation means the controls can be used without any difficult positioning.
Does it require any ongoing maintenance? The self-cleaning nozzle minimises daily maintenance. The water inlet filters (built into the T-piece connector) should be inspected and cleaned periodically, roughly every six months or if water pressure reduces noticeably. The seat itself can be wiped down with a mild, non-abrasive cleaner. Harsh chemicals, including bleach and acidic cleaners, should be avoided as they can damage the components.
The Bottom Line
A wash and dry smart toilet works by drawing cold water from your mains supply, heating it internally, and delivering it through a self-cleaning, adjustable nozzle at the press of a button. A warm air dryer completes the cycle, leaving the user clean and dry without toilet paper, without reaching, and without assistance. The heated seat, night light, deodoriser, and one-touch Auto function are all built around the same core purpose: making the bathroom a more comfortable, more dignified, and more independent experience for everyone who uses it.
Once you understand how it works, the question most people ask isn't "does it really work?"; it's "why didn't I get one sooner?"