If a home has been closed for several weeks, start by flushing water through taps and showers, checking the hot-water equipment and stopping if you find leaks, corrosion or signs of failure. Stagnant water, lukewarm water and rarely used outlets deserve attention because shower aerosols can carry microorganisms. In Lisbon apartments used only at weekends, holiday homes or properties just handed back after building work, reopening the system in a sensible sequence prevents avoidable problems.
Contents
- Why does a closed home change the plumbing routine?
- What should you inspect before turning the water on?
- How should taps and showers be brought back into use?
- When is routine cleaning enough, and when should you call a professional?
- Which mistakes are common after an absence?
- How can you prepare the home for the next period away?
Why does a closed home change the plumbing routine?
A system left unused is not simply on hold: water remains in pipework, flexible hoses, shower heads and sometimes in the hot-water cylinder. The Portuguese Directorate-General of Health explains that Legionella may multiply in low-flow or stagnant circuits, tanks, scale and biofilm, especially where water remains within a favourable temperature range.
The relevant risk for Legionnaires’ disease comes from inhaling contaminated aerosols, rather than drinking water. That makes showers, hand showers, tap aerators and other spray-producing outlets the first places to address when reopening a property. This does not mean that every absence is an emergency. It does mean avoiding a first shower in a closed bathroom while standing close to the spray.
For predominantly residential buildings, Law 52/2018 generally excludes domestic networks from the formal programme required for many publicly accessible places. The law still recognises domestic hot-water networks as systems where prevention and maintenance matter. Read Law 52/2018 for that distinction: a normal home does not need to be operated like a hotel, but sound household practice remains worthwhile.
What should you inspect before turning the water on?
Walk around first, before opening any tap. Look for damp flooring near the cylinder, boiler or heat-pump unit; recent marks inside the cabinet below the sink; greenish or whitish deposits on joints; distorted flexible hoses; and valves that look seized or corroded. If the meter is accessible, note the reading before using water. A change without consumption can point to a leak and merits investigation.
Also check whether there was a power cut, a tripped electrical board or works in the building while you were away. A hot-water cylinder should not be switched on blindly if it may have been empty or if its water supply was interrupted. With gas appliances, do not attempt to solve persistent errors, smells or flue problems by repeatedly restarting the unit.
- Cold water: check for leaks, unusually low pressure or water that stays cloudy.
- Hot water: inspect the appliance, safety valve and any signs of dripping.
- Shower: inspect the hose, holder, enclosure joints and seals around the tray.
- Unused bathroom: check drains for sewer odours; a dry trap is a different issue from water quality.
If larger work is planned, also review what to know about drainage and plumbing before renovation. Incoming water, drainage, ventilation and maintenance access should be planned together.
How should taps and showers be brought back into use?
Open a window first or keep the room ventilated. Begin with cold-water outlets and follow a clear order, such as kitchen first and bathrooms afterwards. Let water run long enough to replace the water sitting in the pipework, without filling containers or standing with your face close to the outlet. For showers, direct the head away from you and step back while water is running.
- Open one cold-water tap and wait for the flow to become steady.
- Repeat at the remaining outlets, including rarely used basins, bidets and outdoor taps.
- Then turn on hot water, starting with one tap and checking that the appliance operates without noise, smell or leakage.
- Finally flush the showers. If the shower head has visible limescale or dirt, remove only the component intended for routine cleaning; do not force old threads.
- Flush toilets and confirm that cisterns refill and stop correctly.
The DGS recommends avoiding stagnant zones and, particularly for larger installations, refers to hot water above 50°C and cold water below 20°C as conditions that make multiplication harder. Read the prevention and control guidance in context: do not change appliance temperatures at random, as there is a scalding risk and every system has its own limits.
When is routine cleaning enough, and when should you call a professional?
Reasonable household cleaning includes removing surface limescale from the shower head, washing aerators in line with the manufacturer’s instructions and removing accessible dust or dirt around equipment. It does not include opening tanks, dismantling safety valves, working on electrical components, interfering with a gas boiler or pouring disinfectants into the system without a diagnosis.
Call a professional if hot water does not stabilise, if the safety valve discharges continuously, if there are rust marks, if pressure fluctuates markedly, if water appears around the appliance or if a leak is visible inside a wall. A home where vulnerable people will stay also deserves careful assessment when the system has been unused for a long period, especially with an older cylinder, auxiliary tanks or several dead-end pipe runs.
Legionnaires’ disease is a pneumonia that can be serious. The DGS lists older age, smoking, lung disease, diabetes, kidney disease and immunosuppression among factors associated with greater susceptibility. Its epidemiological information provides the context. Respiratory symptoms with fever after a concerning exposure are a clinical matter, not a home-repair task.
Which mistakes are common after an absence?
The first is trying to save water by opening one tap for only a few seconds. That leaves several branches of the system untouched. The second is setting the appliance to its highest temperature without checking for a thermostatic mixing valve, the appliance condition or the presence of children and older residents. The third is mistaking a sewer smell for contaminated water: a dry trap can release odours, but it needs water restored to the trap and the drainage checked, rather than random disinfection of the supply network.
Do not close up a damp room immediately after using showers and appliances either. If the home was shut through winter, combine the water restart with a check for condensation, ventilation and leaks. Painting over a mark before its source is resolved only makes diagnosis harder.
For owners who regularly come and go, the most useful prevention is practical: record the last date of use, identify the main shut-off valve, keep the appliance manual accessible and arrange maintenance appropriate to the equipment. A system that can be inspected easily is more likely to reveal faults early.
How can you prepare the home for the next period away?
Before leaving again, decide whether to shut off the main water supply or whether the absence will only last a few days. The right choice depends on duration, the condition of the installation and whether someone can check the home. If you do shut off water, locate and test the valve at a calm time, never minutes before travelling.
Keep access clear to the meter, electrical board and hot-water appliance. Do not stack boxes, laundry or cleaning products against equipment that needs ventilation and servicing. In an apartment, tell a trusted person what to do if they see a leak or a tripped board; in a shared building, keep the managing agent’s contact details for faults that could affect risers or neighbouring homes.
A renovation is the right time to provide zoned isolation valves, access to equipment and clear pipe routes. If you are reviewing these conditions in a Lisbon home, see Obra Lisboa as a construction company and arrange a discussion about the technical scope before walls are closed or equipment is selected.
Key takeaways
- Flush every rarely used outlet before returning to normal daily use.
- Do not alter hot-water temperatures or dismantle equipment without understanding the system.
- Leaks, corrosion, continuous discharge and unstable hot water need professional diagnosis.
- Plan accessible valves and maintenance zones during renovation.
Renovating plumbing, a bathroom or a utility area? Before walls are closed, set out the access panels, isolation valves and equipment positions with a team able to coordinate them within the building work. Discover Obra Lisboa and discuss the practical scope of your renovation.
Sources and further reading
- Portuguese Directorate-General of Health
- prevention and control guidance
- Law 52/2018
- epidemiological information
AI-generated editorial image; it does not depict an Obra Lisboa project.
Obra Lisboa
