[Structural Earthquake Resistance and Business Assets] Will the building’s septic tank and underground sewage pipes break after the earthquake? Underground drainage box culvert inspection and electromechanical equipment post-earthquake repair project in Greater Taipei

Underground hazards: Slight uneven subsidence of foundations caused by earthquakes

In the Taipei Basin and the riverside areas of New Taipei City, such as Sanchong, Luzhou, Wugu, and Xizhi areas where the soil is relatively soft or sandy clay, earthquake shaking will not only destroy the above-ground structure of the building, but also often cause slight "differential settlement" in the foundation of the building. This slight inclination of the foundation will produce huge shear and tensile stresses on the sewage main pipes, septic tanks (sewage treatment tanks) and basement sewage pump sump buried deep in the bottom floor of the building and under the basement RC structure floor. Since underground waterways and septic tanks are mostly made of cement or fiberglass, once broken, sewage and methane will penetrate into the foundation soil and even flow back through cracks in the basement floor, emitting a strong odor. For commercial assets such as office buildings and shopping malls, this is an invisible flaw that directly leads to sharp falls in rents and loss of customers.

Underground septic tanks and sewage main pipes: water leakage and air-tight filling detection

To check whether underground septic tanks and sewage pipelines are damaged, you need to use the "filling pressure maintenance method" and "biogas concentration detection". Plumbing and electrical engineers will first use a pipe plug to seal the outlet end of the sewage pit, then fill the pipeline system and septic tank with water to a specific observation height, and then wait for 24 hours to observe the drop in the water level. If the water level drops significantly, it means the structure is cracked and leaking. At the same time, an all-in-one gas detector is used to measure hydrogen sulfide (H2S) and methane (CH4) concentrations in basement distribution rooms and pipes. If the value is abnormally high, professional mechanical and electrical engineering personnel must be immediately arranged to perform structural reinforcement crack grouting (chemical grouting) or partial pipeline renovation to maintain building hygiene and foundation structural safety.

Post-earthquake emergency repair of sewage motor relay and automatic alternating control panel

The basement sewage sump is usually equipped with a dual-circuit sewage pumping motor. The violent vibrations of earthquakes often cause the float switch mounted on the wall of the sewage pit to shift position and get stuck on the edge of the sump, or the contacts of the electromagnetic contactor (Magnetic Contactor) and automatic alternating relay in the distribution box to loosen and burn due to excessive shaking. Plumbing technicians pointed out that when repairing electromechanical equipment after the earthquake, they must first confirm that the alternating control panel is functioning normally, test whether the operating current of the individual motor is within the rated load, and clean the debris and grease on the float switch. Ensuring that the sewage pumping system can operate automatically and alternately 24 hours a day without failure is the first line of electromechanical defense to prevent basement sewage from overflowing and damaging expensive high and low voltage switchboards.

Commercial property asset defense: CapEx maintenance and renovation bargaining chip

For property investors who specialize in acquiring entire old commercial offices and commercial buildings for asset repositioning (Asset Repositioning), the integrity of the underground sewage system after the earthquake is an important bargaining chip in negotiating price reductions. Since the repair of underground septic tanks and culvert pipes involves structural safety and excavation, the construction cost is extremely high (CapEx budgets usually range from hundreds of thousands to millions of dollars). Entrusting a professional water and electricity inspection team to conduct a complete air tightness, irrigation and endoscopic inspection before the acquisition, and including the damage repair costs into the financial assessment and depreciation, can effectively guarantee the return on investment of the acquisition transaction, and is also a wise move to protect the value of commercial assets.

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

1. 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.
2. 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.
3. 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.