![[Water and electricity renovation acceptance inspection and pit prevention] How to inspect the replacement of water pipes in the whole house? Construction quality indicators of drainage insulation test, 8kg water pressure test for 24 hours and air pressure drop inspection](/images/plumbing-840835_1280.webp)
The worst nightmare of decoration: millions of decorations were destroyed by water leakage in the wall
When renovating old houses or renovating historic houses in Taipei and New Taipei, the most expensive and core foundation project is "re-drawing of whole-house water supply and drainage pipes". Many homeowners and real estate investors spent millions of dollars to build exquisite wooden ceilings and lay high-end marble floor tiles. However, less than half a month after moving in, mold and water began to seep from the corners, and even the wooden floors swelled and rotted due to slight leaks in the water pipes in the walls. After calling in a plumber, we discovered that there were minor flaws when the water pipes were crimped in the wall or when the joints were glued. Once you want to repair it, you must destroy and smash the newly made exquisite decoration! To avoid this kind of disaster, an extremely stringent "dual pressure test and acceptance of water pressure and air pressure" must be carried out before the water and electricity are completed and the wall is sealed with mud (or stone is used to make the leveling).
Fact check: International and Taiwanese standard construction methods for water pipe pressure testing
Generally, the normal operating water pressure of tap water in buildings and apartments in the Shuangbei area is approximately 1.5 to 3.0 kg/cm². If during the completion acceptance, you just open the faucet to see if the water flow is large (static normal pressure test), it will be completely impossible to detect tiny defects in the pipe crimping gap. Small flaws may not leak under low pressure, but when community water pressure rises late at night, or there is water hammer, the joints will burst. Standard water and electricity acceptance must carry out high-voltage pressure test:
1. 8-10 kg/cm² high pressure water pressure holding test (24 hours test)
After all water supply pipelines (cold water pipes, PVC/stainless steel pipes, hot water pipes, stainless steel crimped pipes) are laid, the plumber technician will use a special hydraulic pressure tester (Hydraulic Pressure Tester) to test:
- Use metal plugs (plugs) to completely lock and seal the reserved water outlets of all indoor hot and cold water pipes, and connect the hot and cold water pipe loops.
- Connect the pump to the water line, inject clean water and manually pump the pump until the pressure inside the pipe reaches 8 to 10 kg/cm² (about 3 to 4 times the normal water pressure).
- Close the pressure gauge valve, record the initial pressure value, and let it stand for at least 1 to 24 hours.
- Qualification criteria: Recheck the pressure gauge after 24 hours. The pointer must be completely "zero pressure drop (without any slight decline)", and all wall pipe joints and crimping points must be free of any moisture or tiny water droplets seeping out. This means that the sealing of the water supply system is qualified.
2. High-precision air pressure drop test (Pneumatic Air Pressure Test)
For high-end decoration or commercial properties where construction quality is extremely important, advanced plumbing engineers will also conduct "air pressure testing". The volume of air molecules is much smaller than that of water molecules, so air pressure can detect micro-leaks that cannot be detected by water pressure:
Use an air compressor to inject 6 to 8 kg/cm² of compressed air into the pipe, spray thick soapy water on all pipe crimp joints. If there is a slight crimping failure in the connector, the soapy water will instantly blow up tiny bubbles, which can accurately locate the hidden fault in the wall and replace the connector immediately.
"Acceptance of water supply and full water filling" of drainage and exhaust pipelines
The water supply pipe is tested for pressure, while the pressure-free drainage pipes (sewage pipes, floor pipes, toilet pipes) need to be tested for "drainage slope and smoothness":
- Drainage Slope 1/100 Inspection: Use a laser level to confirm that lateral drainage mains have a downward slope of at least 1% to prevent sewage from retaining and forming sludge.
- Full water level test: Insert the expansion water test air bag at the end of the drainage pipe to seal it, fill the pipe with water to the ground drain outlet, let it sit for 30 minutes, observe whether there is water seepage in the pipe joints, and confirm that the pipe structure is intact before mud work.
- Pipeline endoscope re-inspection: Use the pipeline camera to go 3 meters deep into the pipe to confirm that there is no cement block or sand accidentally dumped during construction.
Water and electricity pressure test acceptance checklist and CapEx guaranteed value
In Shuangbei decoration projects, requiring water and electricity manufacturers to provide a "pressure test signature report" is the best tool to protect the rights and interests of homeowners:
| Acceptance Test Project | Standard Operating Practices | Qualification criteria |
|---|---|---|
| Hydraulic pressure test of hot and cold water pipes | Press to 8-10 kg/cm² and let stand for 24 hours | The pressure gauge has zero pressure drop, and there are no water droplets at the wall pressure points |
| Concealed pipeline pressure test | Air compressor drives in 6 kg/cm² air pressure + soapy water spray test | No bubbles are generated, and the air pressure pointer is stable and does not drop |
| Drain pipe full water filling test | Block the air bag at the end of the pipe, fill the water pipe with water and let it sit for 30 minutes | The water level has not dropped at all, and there is no water seepage in the underground layer |
Conclusion: Defend decoration assets with scientific pressure testing
Plumbing projects are the most concealed and destructive projects in residential decoration. The tightness of pipes inside a wall should never be bet on the intuition of a plumber. Insisting on performing a 24-hour hydraulic pressure test and air pressure inspection of 8-10 kg/cm² before sealing the wall with mud, and keeping complete pressure test photos and data records, can establish the most stringent waterproof insurance for your home and ensure that you will avoid the huge pain and financial losses of wall repairs and pipe repairs for decades to come.
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 the contract for the project, be sure to clearly specify the waterproofing warranty period (usually 1 year for partial repairs, and 2 to 5 years for the whole 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.
