# Bathroom Design and Installations – When Should Plumbing and Electrical Work Be Planned? - URL: https://f-projektow.pl/en/bathroom-design-and-installations-when-should-plumbing-and-electrical-work-be-planned.htm - ID: 434 - Blog: ybc - Published: 2026-09-19T00:00:00+00:00 Plumbing and electrical installations in a bathroom should be planned only after the functional layout of the room has been established, but before installation work, built-in structures and tiling begin. The location of the bathtub or shower, toilet, washbasin, furniture, mirror, washing machine and lighting should determine where individual installation points are positioned – not the other way around. In practice, one of the more common problems during a renovation is starting installation work before the bathroom design has been approved. Only later does it turn out that the drain is in the wrong place, a socket interferes with a cabinet, the power supply for the mirror is outside its outline, or the shower area has not been prepared correctly for a concealed mixer. That is why, when [designing a bathroom](https://f-projektow.pl/en/21-projekt-lazienki-projektowanie-lazienki.html), it is worth treating the interior layout, plumbing and electrical installation as one interconnected system. Decisions made at the design stage are much easier to change than installations already built into walls and floors. ## When Should Plumbing and Electrical Work Be Planned in a Bathroom? The Shortest Answer **Plumbing and electrical installations should be planned after the functional layout and key bathroom fixtures have been approved, but before the installations, built-in structures, waterproofing and tiles are completed.** The safest sequence is as follows: - take accurate bathroom measurements, - establish the functional layout, - choose the type of bathtub, shower, toilet, washbasin and built-in furniture, - determine plumbing and drainage points, - determine electrical points and lighting, - verify all points against furniture, sanitaryware and wet zones, - prepare documentation for contractors, - only then carry out the installations and begin finishing work. The most important rule is simple: **first determine where the bathroom fixtures and equipment will be located, and only then bring water, drainage and power to those locations.** ## Why Should Installations Not Be Designed Before the Bathroom Layout? Installation points are not independent elements of the room. Their location depends directly on the equipment and fixtures. If the position of the washbasin changes, the location of the water supply, drain, mirror, lighting and often the socket changes as well. Moving the shower may require changes to the drain, mixer and lighting. Relocating the washing machine affects the plumbing, drainage and electrical installation at the same time. That is why a good [online bathroom design](https://f-projektow.pl/en/21-projekt-lazienki-projektowanie-lazienki.html) should begin with function rather than the random placement of connections. This is especially important in small bathrooms, where moving a fixture by just a few centimetres can change the width of a passage, the size of a cabinet or the possibility of installing a larger shower. A good example is this [5 m² bathroom design with a shower, washing machine and dryer](https://f-projektow.pl/en/projekt-lazienki-5m2-z-prysznicem-pralka-i-suszarka-jak-zaprojektowac-mala-przestrzen-bez-kompromisow.htm), where all functions must be coordinated with one another from the concept stage. ## Bathroom Design and Plumbing – What Needs to Be Decided? A bathroom plumbing plan should not be limited to marking a few points on the wall. First, the fixtures, installation method and final positions must be determined. ## Washbasin Before the installation points are prepared, it is worth knowing: - exactly where the washbasin will be located, - how wide it will be, - whether it will be countertop-mounted, inset or integrated with furniture, - whether the tap will be deck-mounted or concealed, - what the vanity unit under the washbasin will look like. This is particularly important with drawers. An incorrectly positioned drain or valves may interfere with the drawer mechanism and force later modifications to the furniture. ## Toilet In the case of a toilet, the type of concealed frame, the position of the toilet bowl and the way the enclosure will be built must be established. It is also worth deciding in advance whether there will be a shelf, cabinet or full-height built-in unit above the frame. Moving the toilet should always be analysed in terms of whether the drainage system can be installed correctly. Not every location that looks good on a floor plan is equally easy to execute technically. ## Shower When designing the shower area, the following should be determined in advance: - shower dimensions, - type of drain, - location of the mixer, - position of the rain shower and hand shower, - whether a concealed mixer will be used, - the niche or shelf for toiletries, - the position of the glass panel or shower door. The shower drain in particular should be coordinated with the floor construction and the planned finished floor level. The decision to use a walk-in shower should therefore be made early enough. ## Bathtub A bathtub design should take into account more than just its length and width. The position of the drain, the way the tap is connected, any concealed fittings and service access are also important. If the bathtub is to have lighting, hydromassage or other electrical equipment, an appropriate power supply must also be planned. ## Washing Machine and Dryer A washing machine requires plumbing, drainage and electricity. If it is to be concealed inside built-in furniture, all connections must be planned so that they do not interfere with the appliance and remain accessible. For a tall unit containing a washing machine and dryer, the dimensions of the appliances, the furniture construction, the possibility of removing the appliances and the manufacturers’ installation and ventilation requirements must also be taken into account. ## Bathroom Design and Electrical Installation – What Should Be Planned Before Renovation? Electrical installation in a bathroom involves much more than one ceiling light and a socket near the mirror. Modern bathroom designs often include many more electrical devices, which is why the installation should be coordinated with the detailed interior design. ## Main Lighting First, it is worth determining the location of ceiling lights or other light sources. Their positions should correspond to the actual functional layout of the room rather than an arbitrary ceiling grid. ## Mirror Lighting Already at the design stage, it should be clear whether the bathroom will include: - a mirror with integrated lighting, - wall lights on both sides of the mirror, - a light above the mirror, - LED lighting concealed behind the mirror. The electrical point should be positioned specifically for the chosen solution. Otherwise, the cable may later extend beyond the outline of the mirror or end up behind an element of the built-in furniture. ## Sockets Near the Washbasin It is worth deciding in advance where a hairdryer, shaver, electric toothbrush or other appliances will be used. At the same time, the location of electrical accessories must take into account the safety requirements applicable to rooms containing a bathtub or shower. The final positioning, selection of protective devices, required protection ratings and the method of installing the electrical system should be verified by a suitably qualified electrician and adapted to current regulations and standards. ## Washing Machine and Dryer Power sockets for these appliances are best planned together with the built-in furniture. They should remain accessible while not interfering with the depth of the appliances or their cables. ## LED Lighting If the design includes illuminated shelves, niches, a bathtub, furniture or ceiling lighting, it is necessary to plan not only the cable but also space for the power supply unit and possible service access. This is a detail that is easy to overlook at the visualisation stage but becomes very important when the bathroom is being built. ## Fan, Heating and Additional Equipment Depending on the bathroom equipment, it may also be necessary to provide power for: - a ventilation fan, - an electric radiator, - an electric heating element in a towel radiator, - electric underfloor heating, - an anti-fog mirror, - a smart toilet or washlet seat, - additional decorative lighting. The earlier these decisions are made, the easier it is to prepare the installation without having to cut into finished walls later. ## What Should Be Planned First – Plumbing or Electrical Work? Plumbing and electrical installations should not be treated as two completely separate stages. Both should result from one approved bathroom design. In practice, the process is best started with the sanitary fixtures because their position has the greatest impact on the route of water supply and drainage. Lighting, sockets, appliance power supplies and controls can then be precisely adjusted. For example: - first determine the position of the washbasin, then the mirror and sockets, - first determine the size of the shower, then the lighting around it, - first design the tall unit for the washing machine and dryer, then adjust the connections, - first establish the toilet enclosure layout, then add lighting or sockets in that part of the bathroom. ## Why Does the Choice of Fixtures and Equipment Affect the Installations? Two products serving the same purpose may require different installation preparation. This applies particularly to concealed mixers, toilet frames, drains, bathtubs, illuminated mirrors and shower systems. It is therefore not always necessary to purchase every product before the installations are completed, but it is worth knowing at least the type, dimensions and installation requirements of the selected products. The more unusual the solution, the more important it is to check the manufacturer’s documentation in advance. ## Concealed Installations – Why Must They Be Chosen Early? Concealed mixers, rain showers, toilet frames and other hidden installation components are installed before the final wall surfaces are completed. Changing the decision after the tiles have been laid may require removing finished surfaces. For this reason, the type of fittings should be established at the design stage rather than only when purchasing products several weeks later. The design should also take into account the final thickness of built-in structures and wall finishes. This is particularly important with concealed components, whose position must correspond to the final finished wall surface. ## Can Plumbing Be Relocated in a Bathroom? In many cases, yes, but the possibilities depend on the existing installation, the distance from the main drainage stacks, the building structure and the type of fixture. The most restrictive element is usually the drainage system. Waste pipes require an appropriate route and slope, so there may be less freedom to move a toilet or shower drain than to relocate water supply pipes. The functional layout should therefore not only look attractive but also be technically feasible. ## Does Moving Installations Increase the Cost of a Bathroom Renovation? Usually, yes. The greater the changes to the existing plumbing or electrical installation, the more work needs to be completed before the finishing stage begins. Costs may increase due to: - relocating drains, - changing the position of the toilet, - preparing installations for concealed mixers, - adding electrical circuits, - adding new lighting points, - providing power for underfloor heating, - installing LED lighting systems, - building additional enclosures or service walls. This does not mean that every installation change should be avoided. Sometimes moving a connection by a relatively small distance can create a much better bathroom layout for many years to come. The important thing is to make the decision consciously before work begins. ## The Most Common Mistakes When Planning Bathroom Installations ## 1. Starting Plumbing Work Before the Design Is Ready The contractor positions the installation points according to the existing layout, and only later is the bathroom arrangement created. As a result, the design has to adapt to the installation instead of the users’ needs. ## 2. Planning Sockets Without a Furniture Design Once the built-in furniture is installed, it turns out that the socket is behind a drawer, appliance or tall cabinet. ## 3. Positioning the Mirror Connection “More or Less in the Centre” After a specific mirror is selected, the cable may remain visible or be located in a position that does not meet the manufacturer’s requirements. ## 4. No Power Supply for Additional Equipment An illuminated mirror, LED lighting, radiator heating element, underfloor heating or smart toilet is selected only after the electrical installation has already been completed. ## 5. Choosing a Concealed Mixer Too Late Concealed fittings require installation components to be prepared inside the wall. This is not a decision that should be postponed until the tile-purchasing stage. ## 6. Lack of Coordination Between the Washing Machine and Built-In Furniture The connections take up space required by the appliance, causing the cabinet to become deeper or the washing machine to project beyond the furniture line. ## 7. No Service Access Concealing installations should not mean completely blocking access to components that may require inspection or servicing. ## Bathroom Design Before Renovation – What Should the Contractor Receive? The more decisions are recorded in the documentation before renovation starts, the lower the risk that the design will have to be interpreted directly on site. Depending on the scope of the project, useful documentation may include: - a functional bathroom floor plan, - the location of sanitary fixtures, - the location of plumbing points, - the location of drains, - the location of electrical points, - the lighting layout, - drawings of custom-built furniture, - visualisations showing the final result. At Fabryka Projektów, the scope of documentation depends on the selected package. For a bathroom design, the VIP package also includes the positioning of electrical and plumbing points, allowing the installations to be coordinated with the approved interior layout. See the service details: [bathroom design – online bathroom interior design](https://f-projektow.pl/en/21-projekt-lazienki-projektowanie-lazienki.html). ## What If the Bathroom Is Part of a Complete Apartment Design? With a comprehensive interior design project, installations should be planned not only within the bathroom itself. Electrical systems, lighting and plumbing should be coordinated with the other rooms and with the overall renovation schedule. This is particularly important in newly built apartments, where installation changes are often best determined before finishing work begins. If the project covers the entire interior, see also our [complete apartment design](https://f-projektow.pl/en/27-projekt-mieszkania-projektowanie-mieszkania.html), where the scope of documentation may include the location of electrical and plumbing points for the rooms included in the project. ## Checklist: What Should Be Decided Before Bathroom Installation Work Begins? - Has the layout of the toilet, washbasin, shower or bathtub been finally approved? - Are the dimensions of the key fixtures and appliances known? - Is the location of the washing machine and dryer known? - Has the type of mixer been selected – exposed or concealed? - Has the type of shower drain been decided? - Has the toilet frame enclosure been planned? - Does the plumbing avoid conflicts with drawers and furniture? - Has the main lighting been planned? - Has the method of mirror lighting been determined? - Have all required sockets been planned? - Has power for the washing machine and dryer been planned? - Is power required for LED lighting? - Will there be underfloor heating or an electric heating element in the radiator? - Have all electrical points been checked for safety requirements? - Has access been maintained to components that may require servicing? - Have the contractors received the latest version of the documentation? ## FAQ – Bathroom Design, Plumbing and Electrical Installation ## When is the best time to plan bathroom installations? After establishing the functional layout and key fixtures, but before installation work, built-in structures and tiling begin. ## Should the bathroom design or plumbing come first? The functional bathroom layout should come first. Only then can the exact location of water supply and drainage connections be determined. ## Can the electrical installation be completed before choosing bathroom furniture? It is better to know at least the layout and dimensions of the built-in furniture. This helps ensure that sockets, mirror cables and lighting will not later interfere with the furniture. ## Do I need to choose a specific washbasin before plumbing work begins? You do not always have to purchase it immediately, but it is worth knowing its type, approximate dimensions, the type of tap and the construction of the vanity unit. ## When should I choose a concealed mixer? Before installation work is completed and before the walls are closed. Concealed components require the installation inside the wall or built-in structure to be prepared appropriately. ## Can a toilet be moved to another location? It is often possible, but the extent to which it can be moved depends on the existing drainage system and technical conditions. Such a change is best verified during the layout design stage. ## Can a shower drain be moved? In many bathrooms, yes, but the floor construction and the possibility of routing the drain correctly must be taken into account. With a walk-in shower, this decision should be made particularly early. ## Does a bathroom design include electrical and plumbing plans? It depends on the scope of the service. At Fabryka Projektów, the positioning of electrical and plumbing points is included in the VIP bathroom design package. ## Can installations be changed after the tiles have been laid? Technically, many changes are possible, but they often require cutting into finished walls again, removing tiles and incurring additional costs. For this reason, installations should be finalised before bathroom finishing work begins. ## Summary – Design First, Installations Second Plumbing and electrical systems are among the most important elements of a bathroom design because once walls, built-in structures and tiles are finished, changing them becomes much more time-consuming. The safest sequence is: **measurements → functional layout → fixture and equipment selection → plumbing → electrical installation and lighting → documentation → execution.** This ensures that drains correspond to the actual position of fixtures, sockets work with the furniture layout, lighting matches the mirror design and functional zones, and contractors receive consistent information before starting work. If you are planning a renovation and would like to see the entire interior before the installations are completed, take a look at our [online bathroom design service](https://f-projektow.pl/en/21-projekt-lazienki-projektowanie-lazienki.html). We will prepare the interior layout, visualisations and – depending on the selected package – the documentation required to complete the project.