Plumbing & Water Systems

Most plumbing complaints are not plumbing faults. "No pressure upstairs", "the shower runs cold when the kitchen tap opens", "the drain blocks every few months" are symptoms of a system that was sized for a building that no longer exists, or was never sized at all. The first job on any call is to establish whether the problem is supply, storage, distribution, or the fixture — because each of those is fixed differently and three of them are invisible from the tap the customer is pointing at.

Pressure and flow are different quantities and they fail differently. Pressure is the force available; flow is the volume delivered per minute. A building can have adequate static pressure and still deliver an unusable shower, because the pipe bore, a part-closed valve or a collapsed flexible hose is throttling the flow. Measure both: static pressure with everything closed, running pressure with one outlet fully open, and flow by timing a bucket fill. A large gap between static and running pressure points to a restriction rather than a supply problem. Guessing between the two is what turns a two-hour visit into a two-day one.

Storage is what makes a building independent of an intermittent mains supply, which in most of Kenya is the condition rather than the exception. Sizing follows occupancy and the realistic worst case for supply interruption, not a round number. The tank has to be positioned high enough to develop working pressure by gravity, or the building needs a booster set — and a tank placed just above the ceiling of the top floor will supply that floor at a pressure nobody will accept for a shower. Tank stands carry a serious load when full and are a structural item, not a plumbing one.

Hot water is where hotels and larger residential buildings are let down most often, and almost always through circulation rather than capacity. A cylinder with plenty of stored volume still delivers a cold first minute at a distant outlet if the hot water is not circulated, because the water sitting in the pipe has to be run off first. In a hotel that is a guest complaint on every check-in. A circulation loop with a small pump keeps hot water at the outlets; the loop, its return, its insulation and its balancing are part of the design, not an afterthought bolted on when complaints start.

Thermostatic mixing protects people, and it is not optional in buildings used by guests, patients or children. Stored hot water has to be hot enough to be safe microbiologically; delivered hot water has to be cool enough not to scald. Those two requirements conflict, and a mixing valve at the point of use is how the conflict is resolved. A system that solves it by simply storing at a lower temperature has traded one risk for another.

Materials decide how the installation ages, and mixing them badly decides how fast. PPR is fusion welded and the joint is as strong as the pipe, provided the tool was at temperature and the timing was right — a cold joint looks identical to a good one and fails months later. uPVC is for cold supply and drainage and must not be used for hot. PEX tolerates movement and freezing with fewer joints on a run, but its fittings must match its standard. Copper is reliable but must never be joined directly to galvanised steel: the galvanic couple corrodes the steel, and a dielectric union is what prevents it.

Galvanised steel explains a large share of low-pressure complaints in older Kenyan buildings. It corrodes internally, the bore narrows, and flow falls year by year while the supply itself is unchanged. The building has not lost pressure; the pipe has lost its bore. Replacing fixtures or adding a pump to a building in that condition treats the symptom and often makes the noise and the wear worse.

Water hammer is a pressure wave, and it damages the system that produces it. It appears when a fast-closing valve stops a column of moving water — a solenoid on a washing machine, a lever tap, a float valve slamming shut. The energy goes somewhere: into pipe clips, into joints, into the fixtures at the end of the run. Arrestors, correctly supported pipework and slower-closing valves fix it. Ignoring it means replacing joints repeatedly and never knowing why.

Drainage works on falls, ventilation and access, and the commonest cause of a recurring blockage is one of those three being wrong rather than anything that was put down the drain. Too shallow a fall and solids are left behind by the water; too steep and the water runs away from the solids, which is the failure most people find counter-intuitive. A trap that loses its seal — because the run is unvented and siphons — lets drain air into the room and is a health issue rather than a nuisance. Recurring blockages in the same place are a design fault until proven otherwise.

Backflow prevention is the part of a plumbing system that protects everyone else. A cross-connection between a potable supply and anything else — a storage tank inlet below the water line, a hose left in a filled sink, an irrigation connection — can draw contamination back into the main when pressure drops, and pressure drops are routine on an intermittent supply. Air gaps and check valves at the right points are cheap; the consequence of not having them is not confined to the building that omitted them.

Scale and water chemistry determine how long heaters and fittings last, and they vary enormously across Kenya. Hard water scales heating elements and cylinder surfaces, cutting output and eventually killing the element; the first symptom is usually "the hot water is not as hot as it was" rather than an outright failure. Where a building is fed from a borehole, the water analysis matters as much to the plumbing as it does to the pump — iron, manganese and hardness all shorten fixture life and stain sanitaryware.

Testing is what separates an installation from a hope. Pipework is pressure tested before it is concealed, and the test is held long enough to reveal a weeping joint rather than just a gushing one. Drainage is tested for falls and for seal retention. On an occupied building the work is staged so that each tested section is returned to service before the next is opened — which is how a hotel keeps water on occupied floors while its risers are replaced. Nothing gets buried, boxed in or tiled over until it has passed.