In mid-rise to high-rise apartment buildings and office properties, a water supply pump is essential to deliver water evenly to each unit. There are several water supply methods, and each has a different mechanism and set of characteristics. In this article, we clearly explain for property owners and managers how water supply pumps work, the types of water supply systems, service life, replacement costs, and what to do in the event of a failure.
What Is a Water Supply Pump? What Role Does It Play?
A water supply pump is a pump that draws tap water into each unit of an apartment building, office building, or similar property. In detached houses or low-rise buildings, water can be supplied directly from the water main, but in higher floors water pressure becomes insufficient, so a water supply pump is needed.
By installing a water supply pump, water can be used without issue on both the first floor and the top floor with no difference in water volume. It is widely used not only in high-rise apartments and office buildings, but also in factories and commercial facilities.
What Types of Water Supply Equipment Are Used in Apartment Buildings?
In addition to water supply pumps, apartment buildings also rely on other equipment that is essential for supplying water. Let us review the role of each.
Water Supply Pipes
Water supply pipes are the piping that delivers water from the water main to each unit in the apartment building. They are installed for washbasins, kitchens, bathrooms, and washing machines, and highly durable materials such as stainless steel and rigid PVC are used.
Water Supply Pump
This equipment supplies water to higher floors without reducing water pressure. There are three types: lift pumps, pressure pumps, and booster pumps, which are used according to the application.
Water Storage Tank
This is a tank that stores water supplied from the water utility, and it is also called a receiving tank or rooftop tank. The receiving tank is installed on the first floor or basement of the building, and the rooftop tank is installed on the roof. FRP is common, although some tanks are made of stainless steel.
Pressure Reducing Valve
This equipment keeps water pressure even in each unit and is often installed in front of the water meter.
Why Is Management of Water Supply Equipment Important?
Water supply equipment is infrastructure that is indispensable to daily life. Without it, people cannot drink water or take a shower. If rust develops or contamination from the sewer system occurs, residents may end up using polluted water.
Drainage equipment is equally important, and when it fails, wastewater can no longer be discharged. To protect hygiene, regular inspection and maintenance of water supply and drainage equipment is essential.
What Are the Water Supply Methods for Water Supply Pumps? Four Types and Their Characteristics
There are four water supply methods for water supply pumps. We explain the characteristics of each and the types of buildings to which they are suited.
Direct Water Supply System
This method uses the water pressure of the main line as is to supply water directly. It is used in single-story and two-story detached houses. While no receiving tank is required, the maximum number of floors is restricted by local ordinances, and it cannot be used when water pressure is low. If this system is to be adopted for an apartment building or office building, the relevant ordinances must be checked, and the approximate cost of connection work is about 1 million yen.
Direct Booster Pressure Water Supply System (Booster Pressure Type)
This method supplies water by combining the water pressure of the main line with the pressure of a booster pump. It is used in mid-sized office buildings and apartment buildings. Because no receiving tank or rooftop tank is required, it can save installation space while supplying clean water. However, water pressure drops if the booster pump fails.
Direct Booster Rooftop Tank System (Booster Lift Type)
This method pumps water up to a rooftop tank with a booster pump and then supplies water by gravity. It is suitable for properties where the owner does not want to install a receiving tank, and water supply can continue from the rooftop tank even if the pump fails. Cleaning of a receiving tank is unnecessary, but installation of a pump room is recommended.
Rooftop Tank Water Supply System (Lift Type)
This method installs a receiving tank and a rooftop tank on the roof, sends water up with a lift pump, and then supplies water by gravity. Compared with other methods, electricity costs can be kept lower, and water can still be supplied from the rooftop tank if the pump fails. However, regular tank cleaning, disinfection, and water quality inspections are necessary.
What Are the Advantages and Disadvantages of Each Water Supply Method?
Compare the advantages and disadvantages of each water supply method and choose the one that best fits your property.
Direct Water Supply System
Advantages: No pump or receiving tank required, no installation space required, reduced maintenance costs
Disadvantages: Restrictions under local ordinances, water pressure limits, construction costs of about 1 million yen
Direct Booster Pressure Water Supply System
Advantages: No receiving tank or rooftop tank required, space-saving, preserves appearance, supplies clean water, energy-efficient
Disadvantages: Lower water pressure if the pump fails, no water supply during outages, regional restrictions apply
Direct Booster Rooftop Tank System
Advantages: No receiving tank required, space-saving, no outage even if the pump fails, energy-efficient
Disadvantages: Volatilization of residual chlorine, regional restrictions apply
Rooftop Tank Water Supply System
Advantages: Dual water security even during pump failure or water outage, low electricity costs
Disadvantages: Regular cleaning, disinfection, and water quality inspections are necessary, and the building's appearance may be affected
What Is a Drainage Pump? How Is It Different from a Water Supply Pump?
A drainage pump is a pump that lifts wastewater collected in a drainage tank and discharges it into the sewer system. It serves the opposite role of a water supply pump. There are generally three types: for sewage, gray water, and rainwater, and they are commonly installed underground.
When the building's wastewater pipe is lower than the main sewer line, a drainage pump lifts the wastewater and sends it into the sewer pipe. Under Ministry of Land, Infrastructure, Transport and Tourism regulations, drainage pumps must operate as a pair of two units to prevent stoppages. Choosing the wrong type of drainage pump can cause blockages, so it is important to understand which type of pump is used in your property.
What Is the Service Life of a Water Supply Pump and How Much Does Replacement Cost?
The service life of a water supply pump is generally considered to be 8 years as a repair guideline, 10 years as a service-life guideline, and 15 years as a replacement guideline. This varies depending on the scale of the building, water usage, and maintenance frequency. Because many manufacturers set parts retention periods at 10 years, replacing parts at around the 10-year mark is recommended.
Replacement Cost Guidelines
| Item | Estimated Cost |
|---|---|
| Pump unit replacement | Around 1.5 million yen |
| Total replacement cost | About 3 million yen |
| Small household pump | Less than 100,000 yen |
| Installation in a building with only a receiving tank | 700,000 to 1 million yen |
| Lift pump installation (with elevated tank) | 500,000 to 700,000 yen |
| Booster water supply pump replacement | 1.4 million to 1.7 million yen |
What Should You Do If a Water Supply Pump Fails?
A failure of the water supply pump can lead to water outages, abnormal noises, and noise-related problems, creating the risk of tenant move-outs or rent reductions. Regular inspections in everyday operations are important for early detection and response.
Main Causes of Failure
The causes of water supply pump failures in apartment buildings are primarily damage to parts. In particular, rubber packings and mechanical seals are prone to deterioration over time, and many cases involve cracking or corrosion damage. Other causes include damage to circuit boards, loose screws, clogging by foreign matter, and inverter failure.
Response Methods and Costs
In many cases, repairs are possible by replacing the damaged parts. However, for commercial residential equipment, production of genuine parts often ends after about 10 to 15 years, so if genuine parts are no longer available, consider replacing the pump unit itself. The cost of replacing a booster pump is roughly 1.5 million to 3 million yen, and the time required for replacement is about 3 to 4 hours.
What Is an Overhaul That Helps Extend the Life of a Water Supply Pump?
An overhaul is the work of disassembling a water supply pump, inspecting it, and replacing worn parts. For peace of mind, it is advisable to perform maintenance at around 5 years after installation. The motor section, impeller, casing, and other components are checked, and parts that tend to deteriorate, such as bearings and packings, are replaced.
On the other hand, an overhaul after 10 years is not only costly but also has a high chance of being impossible to repair, so in many cases it is more rational to consider replacing the unit itself.
What Are the Key Points in Choosing an Inspection and Repair Company for Water Supply Pumps?
It is important to obtain free quotations from multiple companies and compare costs and scope item by item. Comparing quotations under the same conditions is effective. It is also reassuring to choose a company with a strong track record that publishes case studies on its website.
Water supply pumps are equipment that people rarely see in daily life, but if they fail, they can cause a water outage. To help build a stress-free property management system, acquire the basic knowledge and practice regular maintenance while also referring to the guide to legal regulations.
Frequently Asked Questions (FAQ)
Q. What is the service life of a water supply pump?
It is generally considered to be 8 years as a repair guideline, 10 years as a service-life guideline, and 15 years as a replacement guideline. The actual timing varies depending on the scale of the building and maintenance frequency.
Q. How much does it cost to replace a water supply pump?
The market guideline is around 1.5 million yen for the pump unit alone, and about 3 million yen in total including removal and construction costs. For a small household pump, it may be less than 100,000 yen.
Q. What should I do if a water supply pump fails?
First, check whether a water outage has occurred, and promptly contact a specialist contractor. In many cases, repair is possible by replacing parts, but if the pump has been in service for more than 10 years, please consider replacing the unit itself.
Q. Which of the four water supply methods should I choose?
This depends on the scale, number of floors, and location conditions of the building. Direct water supply is common for low-rise buildings, direct booster pressure systems for mid-sized properties, and rooftop tank water supply systems for high-rise buildings. Local ordinances must also be checked.
Q. When should an overhaul be carried out?
It is recommended to carry it out at around 5 years after installation. After 10 years, there are many cases where replacing the unit itself is more rational than an overhaul.
