There is a sound of rushing water from the top floor in the middle of the night? Watch out for water bills that could skyrocket by tens of thousands of dollars!
In old apartments or luxury buildings in Taipei and New Taipei City, the stainless steel water tower on the top floor is the core of the daily drinking water and bathing water supply for the entire building. However, many residents often hear the endless running of the pumping motor on the top floor in the middle of the night. When they go to the top floor, they find that the water tower is full of water and the overflow hole is draining a large amount of water like a waterfall. The water flows wildly along the drain pipe or parapet wall. This not only wastes precious tap water, but may also cause the pump motor on the first floor to overheat and burn due to continuous idling for a long time, and even trigger a public safety fire.
In-depth analysis of the two main culprits of water tower overflow and abnormal pumping
The water inlet and water replenishment control of the water tower are mainly responsible for the division of labor between two completely different sets of mechanical and electrical components:
- Tap water direct pressure inlet end: mechanical float valve (Float Valve) failure:Tap water pipelines are usually sent directly to the water tower by natural water pressure. A copper or stainless steel "floating ball" is installed at the top of the water tower. When the water surface rises to the set height, the hollow float floats and drives the connecting rod to press the water stopper to close the water inlet. If the waterproof skin is worn and deformed due to sediment and scale in the water, the float ball is broken and sinks to the bottom, or the float connecting rod is rusted and stuck, tap water will be injected into the water tower 24 hours a day and discharged through the overflow pipe.
- First floor pumping motor control terminal: Radar liquid level switch (Liquid Level Controller) abnormality: If the water tower is supplied from the first floor reservoir through a pressurized pumping motor, two orange or black weight floats (commonly known as radar level controllers, such as Taiwan-made Radar ST-70AB) will be suspended inside the water tower. When the water level drops to the lower limit weight (A2), the internal contact of the switch closes to start the motor; when the water level rises to the upper limit weight (A1), the contact opens to stop the motor. If the two weight suspension wires become tangled, the float ball loses its buoyancy due to water ingress, or the micro switch contacts inside the switch become oxidized and stuck, the motor will not be able to stop at all or refuse to start.
Key points for selecting and upgrading water tower water level control equipment
To completely solve the water tower overflow problem, plumbers recommend upgrading more durable components during maintenance:
- Switch to all stainless steel SUS304 Float water inlet valve:The traditional brass connecting rod and plastic float that are prone to oxidation and breakage are eliminated and replaced with an all-stainless steel valve body with a wear-resistant silicone water stop valve core that can withstand high pressure and has a service life of more than 10 years.
- Regularly check the length of the liquid level controller sling: The upper limit weight (A1) should be set at least 10 to 15 cm below the overflow port of the water tower, leaving a sufficient buffer safety distance; the lower limit weight (A2) should be set at least 15 cm above the water outlet of the water tower to prevent the water level from being too low and inhaling sediment at the bottom of the water tower.
- Install a "waterless power-off protector" on the pumping motor: An anti-idling protection device is installed on the control circuit of the pumping motor on the first floor. Once the tap water is cut off or the water inflow is insufficient, the motor senses that there is no water flow and will automatically cut off the power within 1 to 3 minutes to prevent the motor shaft seal from being worn and burned.
Tap water tower cleaning cycle and standard process specifications
According to the official recommended standards of the Taipei Water Works Agency and the Taiwan Water Company, water towers and reservoirs in apartment buildings should be "cleaned regularly at least once every six months":
- Qualified vendors and safe ventilation: Cleaning operations should be entrusted to professional water tower cleaning vendors recognized by the Water Works Agency. Forced ventilation and measurement of oxygen concentration are required before entering the confined space of the water tower.
- It is strictly forbidden to use strong acid and strong alkali chemicals: Only high-pressure water purifiers, soft brushes and sodium hypochlorite disinfectant that meet food-grade standards can be used to clean the inner wall of the water tower. It is strictly forbidden to use hydrochloric acid or strong corrosive chemical detergents to avoid damaging the passivation protective layer of stainless steel and contaminating drinking water.
- Inspection of falling water insect-proof nets and breather pipes: The manhole cover at the top of the water tower must have an airtight seal and be tightly locked; the breather pipe outlet must be equipped with a fine stainless steel insect-proof and bird-proof net of more than 16 mesh to prevent geckos, cockroaches, mosquitoes and flies from falling into the water and causing secondary pollution.
Neighborhood Management Committee Water and Electricity Inspection Checklist
It is recommended that apartment residents or the management committee arrange a rooftop inspection every quarter: check whether there are traces of moisture and water overflow around the water tower, listen to whether the sound of the motor is running smoothly without sharp bearing noise, and check whether the cable duct is damaged or cracked. Spending a few hundred yuan to replace the aging float valve as soon as possible can protect the pure and safe water quality of the entire building and save tens of thousands in unnecessary utility bills.
The latest standards for catching leaks and regulatory responsibilities in Shuangbei collective housing (2025-2026 practice)
According to Article 10 of the "Apartment Building Management Regulations" of the Ministry of the Interior and the trend of civil water leakage judgments in Shuangbei District Court in recent years, most water leakage disputes in old collective housing focus on the identification and definition of "exclusive parts" and "common parts". The roof platform and the public pipes are jointly owned by all separate owners, and the repair costs should be shared by public funds or all residents in proportion to their shares according to law; if the water supply and drainage pipes inside the floor slabs on the upper and lower floors are damaged, the pipes will be borne exclusively by the users or shared by the upper and lower floors.
At the engineering and technical level, modern professional leak detection has fully introduced non-destructive scientific testing, including "FLIR high-resolution infrared thermal imaging camera" (locating temperature difference leakage paths), "high frequency moisture meter" (measuring the moisture content of deep structures) and "pipeline air pressure and water pressure pressure test" (determining whether hot and cold water pipes are leaking). During construction, do not directly apply elastic cement or oil-based paint on the wet cement layer to seal it. Otherwise, the thermal expansion of internal water vapor will quickly cause the coating to blister and peel off, resulting in more serious powdery wall cancer. The standard construction method must first completely eliminate the water source, wait until the moisture content of the cement structure drops below 8%, and then apply the negative pressure resistant silicic acid permeability crystallized waterproof layer.
Recommendations on independent certificate storage and compensation process for water leakage repair
- Take photos and videos as evidence immediately: Use rulers to record the leakage range, frequency of water discharge, direction of water mark diffusion, and keep time stamps.
- Written notification and coordination survey: Officially notify the neighbors through the management committee or a certified letter, and agree on a professional third-party leak detection and appraisal unit recognized by both parties to conduct an on-site survey.
- The contract states the warranty terms:When signing a contract for a project, be sure to clearly specify the waterproofing warranty period (usually 1 year for partial repairs, and 2 to 5 years for complete room or roof re-construction), and specify the water test acceptance criteria (such as a 48-hour water storage test in the bathroom shower area) to protect your own asset rights.
