BHU Certification Glossary
22 Key Terms Every Landlord Must Know
The Basic Housing Units Ordinance is filled with precise legal terms — "Subdivided Unit" and "Basic Housing Unit" are not interchangeable; "Housing Bureau" and "Buildings Department" have entirely different roles; "Grace Period" and "Validity Period" apply at different stages. This glossary defines all 22 terms based on the actual ordinance text, so landlords can read the law accurately and communicate clearly with their Specified Professional.
22 Core Terms at a Glance
| Category | Terms | Source |
|---|---|---|
| Identity (4) | Subdivided Unit, Basic Housing Unit, Host Flat, Registered Flat | ss. 2, 4 |
| Parties (4) | Secretary (Housing Bureau), Buildings Department, Specified Professional, Site Inspection | s. 2, Sch. 3, s. 17(2) |
| Time & Dates (6) | Gazettal Date, Registration Period, Grace-period Registration, Grace Period, Validity Period, Code of Practice | ss. 1, 2, 9, Sch. 2 |
| Standards (4) | Minimum Standards, Internal Floor Area, Clear Ceiling Height, Air Change Rate | Sch. 1 |
| Fees & Penalties (4) | Prescribed Fee, Level 6 Fine, Conviction on Indictment, Daily Default Fine | Sch. 2, s. 8(3) |
Source: Basic Housing Units Ordinance (Cap. 658, Hong Kong), in force from 1 March 2026
1. Identity Terms: What Is What?
The ordinance uses different names to describe the same physical space at different stages of its legal status. These four terms are the foundation.
Subdivided Unit (SDU)
分間單位Ordinance (s. 4): A compartment within a residential flat that was partitioned in a manner not shown on the approved plans and is designed to be let independently.
Why it matters: "Subdivided Unit" is the status before certification. The ordinance regulates SDUs. Once certified, the unit becomes a "Basic Housing Unit." If the certificate lapses without renewal, it reverts to SDU status.
Basic Housing Unit (BHU)
簡樸房Ordinance (s. 2): A subdivided unit for which a valid Basic Housing Unit recognition is in force.
Why it matters: "BHU" is a legal term, not a colloquial name for any subdivided flat. A flat is only a "BHU" while its certificate is valid. Using the term for an uncertified flat is legally inaccurate.
Host Flat
主樓宇單位Ordinance: The entire residential flat that was subdivided — the unit whose title the landlord holds in the Land Registry.
Why it matters: Applications for certification are made at the host flat level, covering all subdivided units within it. A landlord with one flat subdivided into three units makes one application covering all three.
Registered Flat
登記樓宇單位Ordinance (s. 2): A flat for which a valid grace-period registration is in force.
Why it matters: Once a landlord registers before 28 February 2027, their host flat becomes a "Registered Flat" — protected by the grace period until 28 February 2030.
2. Party Terms: Who Does What?
Landlords frequently confuse the Housing Bureau and the Buildings Department. Understanding who administers BHU certification — and who simply approves building works — is essential.
⚠️ Most Commonly Confused: Housing Bureau vs Buildings Department
| Body | Role | Legislation |
|---|---|---|
| Housing Bureau | Administers BHU certification and grace-period registration (the "Secretary" in Cap. 658 is the Secretary for Housing) | Cap. 658, s. 2 |
| Buildings Department | Approves building works and enforces the Buildings Ordinance (Cap. 123) — separate from BHU certification | Cap. 123 |
Specified Professional
指明專業人士Ordinance (Schedule 3): Any person from the following three categories:
- A Registered Architect listed in the architects register (Cap. 408)
- A Registered Professional Engineer in the building, building services, civil, fire or structural engineering disciplines (Cap. 409)
- A Registered Professional Surveyor in the building surveying division (Cap. 417)
Why it matters: Every BHU certification application must include a report by a Specified Professional based on a site inspection. The professional bears legal responsibility for the contents of that report.
Site Inspection
實地視察Ordinance (s. 17(2)): Unless the required report is prepared on the basis of a site inspection of the host flat (including the subdivided unit) carried out or arranged by the Specified Professional, the application is treated as not meeting the requirements.
Why it matters: The Specified Professional must physically inspect — they cannot rely solely on floor plans, photographs or descriptions provided by the landlord. This is a mandatory statutory requirement, not a professional preference.
3. Time and Date Terms: Know the Deadlines
According to the Basic Housing Units Ordinance, several hard deadlines determine the fees you pay and the protection you receive. Missing them has real financial consequences.
Gazettal Date
刊憲日 · 3 Oct 2025Ordinance (s. 2): The date on which the ordinance was published in the Gazette — 3 October 2025.
Why it matters: Eligibility for grace-period registration requires that the subdivided unit was let as a residential tenancy at some point in the 3-month window ending on the gazettal date (i.e. 4 July to 3 October 2025).
Registration Period
登記期 · 12 monthsOrdinance (s. 10(1)(d)): The 12-month period beginning 1 March 2026 — i.e. 1 March 2026 to 28 February 2027.
Why it matters: Landlords must apply for grace-period registration within this window. The prescribed fee during this period is $0. After 28 February 2027, the registration fee rises to $745 per flat, and grace-period protection is lost.
Grace-period Registration
寬限期登記Ordinance (s. 9(2)): A registration made by the Secretary for an eligible flat upon application by the owner during the registration period.
Why it matters: Registration is the step that activates the grace period. It does not mean the unit is certified — it simply grants time to complete certification before 28 February 2030 without committing a criminal offence.
Grace Period
寬限期 · 36 monthsOrdinance (s. 9(3)): The grace-period registration remains valid for 36 months after the close of the registration application period — i.e. until 28 February 2030.
Why it matters: The grace period is a buffer, not a permanent exemption. After 28 February 2030, uncertified subdivided units in registered flats will no longer be protected and cannot be lawfully let.
Validity Period
有效期 · 60 monthsOrdinance (s. 16(2)): A recognition granted under s. 16(1) is valid for 60 months (5 years) from the date of recognition (not the application date).
Why it matters: Landlords must apply for renewal before the 60-month period expires. The renewal fee is $2,400 per BHU. A lapsed certificate returns the unit to SDU status, requiring a fresh certification application.
Code of Practice
實務守則Ordinance (s. 84(1)): Technical guidelines issued by the Secretary for the implementation of the ordinance — the reference document for Specified Professionals conducting site inspections.
Why it matters: The Code of Practice supplements Schedule 1 minimum standards with detailed measurement methods, construction specifications and compliance techniques. Landlords planning renovation works should ask their Specified Professional to reference the applicable Code of Practice sections.
4. Technical Standards Terms: Schedule 1
Schedule 1 of the ordinance sets out 8 categories of minimum living conditions. These 4 terms appear most frequently in assessment reports and renovation contracts.
Minimum Standards of Living Conditions
居住環境最低標準Ordinance (s. 2(2)): A subdivided unit meets the minimum standards if it satisfies all applicable provisions in Schedule 1, covering: floor area, ceiling height, fire safety, loading, private bathroom, water point outside bathroom, lighting & ventilation, and water/electricity meters.
Why it matters: All 8 categories must be met for certification. In practice, ventilation, fire safety and floor area are the three most common failure points.
Internal Floor Area
內部樓面面積 · ≥ 8 m²Ordinance (Sch. 1, s. 1(2)): The floor area measured from the internal face of the enclosing structures, minimum 8 sq m. The bathroom is included in the measurement.
Why it matters: Measured on-site from internal wall face to internal wall face — floor plan figures are not the legal standard. Bathroom counts toward the 8 sq m.
Clear Ceiling Height
樓底淨高 · ≥ 2.3 mOrdinance (Sch. 1, s. 2): The height from floor to ceiling must be at least 2.3 m; where there is a beam, the clear height below the beam must be at least 2.0 m.
Why it matters: Measured at the lowest point — including below false ceilings and AC ducting. Structural beams follow a lower threshold (2.0 m rather than 2.3 m).
Air Change Rate (ACH)
換氣次數 · ≥ 5 ACHOrdinance (Sch. 1, s. 7): Where natural ventilation is not available, mechanical ventilation must supply fresh air at a rate of at least 5 air changes per hour (ACH). This applies to all rooms (including kitchens, excluding bathrooms) and separately to bathrooms.
Why it matters: The specific number (5 ACH) is what engineers use to size mechanical ventilation fans. When renovating, the Specified Professional will calculate the unit's air volume and specify a fan with sufficient CFM output to meet the 5 ACH threshold.
5. Fees and Penalties: Specific Numbers Matter
According to Schedule 2, the prescribed fee is not a flat HKD 3,000. And the penalty structure has three layers — most summaries only quote one of them.
Prescribed Fee
訂明費用 · from $0Ordinance (Schedule 2): Government fees payable to the Housing Bureau, calculated based on the combination of registration application date and certification application date:
- Registration fee: $0 within the registration period (Mar 2026–Feb 2027); $745/flat thereafter
- Certification fee (early-bird): Register Mar–Aug 2026 and certify before Mar 2029 → $0
- Certification fee (late registration): Register Sep 2026–Feb 2027 and certify between Mar 2028–Feb 2029 → $1,500 per SDU
- Certification fee (standard): No early-bird qualification, or outside the windows above → $3,000 per SDU
- Renewal fee: $2,400 per BHU
Why it matters: The prescribed fee is only the government charge — it does not include the Specified Professional's assessment fee or any renovation costs.
⚠️ Penalty Terms: Three-Layer Structure
Ordinance (s. 8(3)): From 1 March 2027, letting an uncertified subdivided unit attracts the following penalties:
| Procedure | Main Penalty | Daily Fine |
|---|---|---|
| Level 6 Fine Summary conviction |
Level 6 fine + 2 years' imprisonment | $20,000/day |
| Conviction on Indictment Indictment |
Fine of $300,000 + 3 years' imprisonment | $20,000/day |
Daily Default Fine: In addition to the main penalty, a further fine of $20,000 per day applies for each day the offence continues — regardless of whether the conviction was by summary procedure or indictment.
Frequently Asked Questions
What is the difference between a "Subdivided Unit" and a "Basic Housing Unit"?
A Subdivided Unit (SDU) is the uncertified status — a partitioned residential flat subject to the ordinance. A Basic Housing Unit (BHU) is the same physical space after it has received a valid recognition from the Housing Bureau. The BHU certificate is valid for 60 months. If it is not renewed, the unit reverts to SDU status. The terms refer to different legal states of the same space, not different types of flat.
Which government department handles BHU certification — the Housing Bureau or the Buildings Department?
The Housing Bureau. Under Cap. 658 s. 2, the "Secretary" referred to throughout the ordinance is the Secretary for Housing. All BHU certification applications and grace-period registration applications are submitted to the Housing Bureau. The Buildings Department administers the Buildings Ordinance (Cap. 123) and handles building works approval — a separate process that may be required when carrying out renovation works for certification, but is not the BHU certification authority.
What is the difference between the Grace Period and the Validity Period?
The Grace Period (36 months, expiring 28 February 2030) is the window before certification during which a registered flat is protected. The Validity Period (60 months from the date of recognition) is the lifespan of a certificate after certification is granted. One is a runway to reach certification; the other is the shelf life of the certificate itself.
Is a "Specified Professional" the same as an "Authorized Person (AP)"?
The terms overlap but come from different ordinances. Under Cap. 658, a "Specified Professional" is any one of three categories (registered architect, registered professional engineer in specified disciplines, or building surveying registered professional surveyor — Schedule 3). An "Authorized Person" under the Buildings Ordinance (Cap. 123) is typically a registered architect or engineer approved by the Buildings Department. In practice, most BHU assessments are carried out by professionals who qualify under both definitions, but strictly speaking the terms originate in different legislation.
Is the prescribed fee always $3,000? How much do early-bird landlords pay?
The prescribed fee is tiered under Schedule 2 of Cap. 658 — it isn't a flat $3,000, and it isn't just a $0-or-$3,000 choice either. Early-bird landlords (registered Mar–Aug 2026, certified before Mar 2029) pay $0. Landlords who registered Sep 2026–Feb 2027 pay $1,500 per subdivided unit if they certify between Mar 2028 and Feb 2029. The standard fee of $3,000 per subdivided unit applies to everyone else — no early-bird qualification, or certification outside the windows above. These are government fees payable to the Housing Bureau and do not include professional assessment fees or renovation costs.