In Japan, the water meter serving a residential building is subject to a legal requirement found in the Measurement Act (keiryo ho), the national law that governs weights and measures: it must be replaced every eight years. Failing to replace it on time can expose the owner to a criminal penalty, and yet a surprising number of landlords have never heard of this rule at all.
This article walks through what a water meter actually does, the difference between meters installed by the public water utility and meters installed privately by the building owner, who is responsible for paying to replace one, exactly how the replacement process works, and the situations where a replacement turns out to be difficult to carry out.
What is a water meter?
A water meter is the device that measures how much water a household has used. Its two main jobs are letting the utility read consumption in order to calculate the water bill, and helping confirm whether there is a leak somewhere in the plumbing. Whether or not the small pilot wheel inside the meter is spinning tells you, at a glance, whether water is currently flowing somewhere it should not be.
The difference between a direct read display and a dial display
| Direct read type | Dial type | |
|---|---|---|
| Appearance | A digital style number counter | Six round dials with a black needle on each |
| How to read it | Read the white digits from left to right | Read each dial's needle in turn, starting from the bottom left and moving clockwise |
| Advantage | Usage is obvious at a single glance | — |
| How common it is | The standard type found in most buildings today | Mostly found in older buildings |
Where the water meter is located, by building type
| Building type | Where the meter sits | Notes |
|---|---|---|
| Condominium or apartment building | Near the entrance of each unit, inside a pipe shaft | Sometimes behind a locked panel. Managed by the management company or the building owner |
| Low rise rental building | Buried in the ground somewhere on the property | All the individual unit meters are grouped together in the same spot, so it is easy to misread the wrong one |
| Detached house | Along the sidewalk or road just outside the property line | Positioned somewhere convenient for the meter reader to access |
| Commercial building | Somewhere not obvious to the average visitor | Deliberately hidden to deter tampering. Only the building manager knows where it is |
The difference between publicly installed and privately installed meters
| Publicly installed meter | Privately installed meter | |
|---|---|---|
| Who installs it | The local water utility | The building owner |
| How the water bill is collected | The utility bills and collects directly from each individual household | The building owner pays the utility a single combined bill, then collects reimbursement from each household |
| Who pays to replace it | The utility replaces it for free | The building owner pays for it |
| Advantage | No billing or collection work for the owner | Lower upfront cost, since no construction work or utility hookup fee is required |
| Disadvantage | Requires construction that meets the utility's building standards, plus a hookup fee, before the connection can even be made | A meaningful ongoing administrative burden: reading meters, billing tenants, and collecting payment |
Owners who want to reduce the administrative burden of a privately installed meter setup can outsource property management to a management company, which can also take over the meter reading, billing, and collection work.
Water meters must legally be replaced every eight years
The validity period set by the Measurement Act
Japan's Ministry of Economy, Trade and Industry enforces the Measurement Act, which sets the validity period of a water meter at eight years. This is a distinctly Japanese requirement: unlike jurisdictions where a water utility replaces meters on its own internal maintenance schedule with no fixed statutory deadline and no penalty attached to the property owner, Japanese law treats a water meter past its eight year validity period as a device that is no longer legally certified to measure water accurately, and it makes replacement compulsory rather than optional. There are two stated reasons a fixed replacement cycle is required:
- The risk that long term use causes the accuracy of the measurement itself to drift
- The risk that a change in how water is actually being used pushes flow beyond what the meter was built to handle, accelerating wear
The penalty for failing to replace a meter on time
The Measurement Act backs this requirement with a real penalty: imprisonment of up to six months, a fine of up to five hundred thousand yen, or both penalties imposed together. This combination of a criminal penalty for a purely administrative lapse is unusual by international standards, and it is precisely why the rule is worth understanding even though it rarely makes the news.
Validity periods for other types of measuring instruments
| Instrument | Validity period |
|---|---|
| Water meter | 8 years |
| Hot water meter or heat quantity meter | 8 years |
| Gas meter | 7 to 10 years |
| Electricity meter | 5 to 10 years |
How to check a meter's validity period
The date is printed on the underside of the meter's cover, on its sealing cap, or on a sticker along its side. A notation such as "10/12" means the meter expires at the end of December in the tenth year of the current Japanese imperial era; more recently, meters have increasingly shown the Western calendar year and month instead.
How a publicly installed meter gets replaced
- Notice is delivered — a contractor working on behalf of the water utility sends a notice stating the scheduled replacement date
- The work itself — the water supply is shut off, the meter is swapped, and the supply is turned back on. If the property has a meter bypass unit installed, the water never needs to be shut off at all
- A completion notice arrives — a card is delivered afterward showing the replacement date along with the final reading on the old meter and the starting reading on the new one
No one needs to be present if the meter is located outdoors. If the meter is located indoors, someone does need to be present to let the contractor in.
How a privately installed meter gets replaced
- Removing the old meter — confirm the correct unit number, remove the freeze protection cover, and shut off the water using the valve. Be careful of residual water left inside the old meter
- Flushing the pipe and installing the new meter — run water through the line to flush out any debris, then check the direction arrow on the new meter before installing it
- Confirming the water flows properly — open the valve slowly to avoid a water hammer, then check every connection point for leaks
Five situations where a meter replacement becomes difficult
- A broken shutoff valve — if the water supply cannot be shut off, the work cannot proceed at all, and a plumbing contractor needs to repair the valve first
- Corroded water piping — there is a risk that the supply pipe itself could fail under the impact of the work, so the piping needs to be repaired before anything else can happen
- Belongings stored on top of the meter — without room to work, the items need to be cleared out of the way beforehand
- No access to the property — a locked gate or similar obstacle means the owner needs to arrange for the contractor to be able to get in on the scheduled day
- Personal items stored inside the pipe shaft — the contractor cannot take responsibility for damage to items left inside, which makes the work difficult to complete safely
What to tell tenants about the meter box
- Do not place anything around it — this can get in the way of a meter reading and lead to an inaccurate reading
- Do not put anything inside it — items touching the wiring can create a risk of electrical leakage, shock, or fire
- Do not use it to store valuables — this invites theft or loss
What to watch for after a replacement
- The water may run cloudy or slightly white for a short time afterward
- Before using a toilet, water heater, or water purifier, run the tap first and confirm the water has become clear
- If no water comes out or another problem appears, contact the contractor or the water utility rather than attempting to fix it yourself, since an inexperienced attempt can create a secondary problem
Summary
Under Japan's Measurement Act, a residential water meter must legally be replaced every eight years, and failing to do so exposes the owner to a criminal penalty. A publicly installed meter is replaced for free by the water utility, while a privately installed meter is replaced at the building owner's own expense, which makes it essential to keep track of when each meter's validity period actually expires. It is also worth making sure tenants understand a few basic rules about keeping the area around the meter box clear, so that a future replacement can go smoothly.
INA&Associates Inc. provides comprehensive rental property management services that include managing water meters on behalf of owners. Please feel free to reach out with any questions about building equipment and facilities management.
