Apartment owners' association vs cooperative society in Karnataka: which one you'll have

Rules and rates as of 16 October 2026.

Buy a flat in Mumbai and you will almost certainly end up in a cooperative housing society. Buy one in Bengaluru and the answer is usually different: an apartment owners' association under a 1972 Karnataka law that many buyers have never heard of. Which body runs your building decides who sets the maintenance, how your share is worked out, and who you complain to. This explainer sets out the two routes, and what the Karnataka High Court has said about which one applies.

What RERA says, and what it leaves to the state

Section 11(4)(e) of the Real Estate (Regulation and Development) Act, 2016 requires the builder to "enable the formation of an association or society or co-operative society, as the case may be, of the allottees, or a federation of the same, under the laws applicable". Only where there are no local laws does a fallback apply: the association must be formed within three months of a majority of allottees booking. Section 19(9) puts a matching duty on buyers to "participate towards the formation" of that body.

So RERA does not choose the form. It points to state law. In Karnataka, two state laws compete for the job.

Route one: the Karnataka Apartment Ownership Act, 1972

The Karnataka Apartment Ownership Act, 1972 (Karnataka Act 17 of 1973, in force from 1 April 1975) works through a document called the Declaration. Under section 2, the Act applies only to property whose owner or owners submit it to the Act by executing and registering a Declaration, and only if the property is "mainly used, or proposed to be used for residential purposes".

Once it applies, each flat becomes a separate unit, and its owner gets an undivided interest in the common areas at the percentage set out in the Declaration. Section 6(1) says that percentage is computed by taking the value of the apartment relative to the value of the property as a basis. Section 10 then shares common profits and common expenses among owners "according to the percentage of the undivided interest".

The body that runs the building is the Association of Apartment Owners, defined in section 3(d) as all of the apartment owners acting as a group under the bye-laws and Declaration. Section 16 requires the bye-laws to provide for a Board of Managers, a President, a Secretary and a Treasurer, and for how owners' shares of common expenses are collected.

Two provisions matter to a buyer of a resale flat. Section 19 makes unpaid maintenance dues a charge on the flat, ranking ahead of all other charges except government and municipal taxes and sums due on a first mortgage. Section 20 makes a buyer jointly and severally liable with the seller for dues unpaid at the time of sale, though the buyer can ask the Secretary or Board of Managers for a statement and is not liable beyond the amount stated.

Route two: a cooperative society

The Karnataka Co-operative Societies Act, 1959 allows registration of a society whose objects are "the promotion of the economic interests or general welfare of its members". Where all the applicants are individuals, section 6(2)(b) requires at least ten of them. The Registrar of Co-operative Societies registers the society and supervises it. In a society, members hold shares in the society, and the society's bye-laws set out how charges are levied.

A third Karnataka law, the Karnataka Ownership Flats Act, 1972, is where the cooperative route for flats comes from. As quoted by the High Court, its section 10 requires the promoter, once enough people have taken flats "to form a co-operative society or a company", to apply to the Registrar within the prescribed period.

What the High Court decided

The question came up directly in Proposed Starnest Apartment Owners Co-operative Society Ltd. v. State of Karnataka (Writ Appeal 564/2024, decided 18 June 2024 by a Division Bench led by the Chief Justice). A group in a Bengaluru project had obtained the Registrar's permission to collect shares for a cooperative society. Other flat owners objected that the project had only residential units and should have an association under the 1972 Apartment Ownership Act.

The court agreed with the objecting owners and upheld a single judge's direction that an association be formed under the Apartment Ownership Act. Its reasoning:

• The Apartment Ownership Act applies to property mainly used, or proposed to be used, for residence. The Ownership Flats Act covers premises used for residence, office, showroom, shop or godown. This project had only residential units.
• The sale deeds recorded that "the parties in the sale deed have agreed to abide by the provisions of the Karnataka Apartment Ownership Act, 1972".
• RERA's sections 11(4)(e), (f), (g) and 17 "only mandate formation of association of the allottees under the applicable laws", and here "The law applicable in the present case is the Karnataka Apartment Ownership Act, 1972".
• The argument that flats might one day be used commercially was rejected as "farfetched".

The judgment turned on that project's facts. A mixed-use building, or a deed that says something different, could point the other way, so read your own documents.

The two side by side

Point	Apartment owners' association	Cooperative society
Law	Karnataka Apartment Ownership Act, 1972	Karnataka Co-operative Societies Act, 1959 (route via Ownership Flats Act, 1972)
Typical building	Mainly residential	Mixed use, or where documents adopt it
Founding document	Registered Declaration, bye-laws, Deed of Apartment	Registered bye-laws; at least 10 individual applicants
What you own	Your flat plus an undivided % of common areas	Your flat, plus shares in the society
How costs are shared	By undivided interest % (s.10), based on value (s.6)	As the society's bye-laws provide
Unpaid dues	Charge on the flat (s.19); buyer liable with seller (s.20)	Recovered under the society's law and bye-laws
Copies filed with	Registrar of Co-operative Societies, as "competent authority" (s.3(i))	Registrar of Co-operative Societies

Worked example: splitting maintenance and corpus by undivided share

This is illustrative. Take a 100-flat residential complex whose Declaration values the whole property at ₹125 crore. Monthly common expenses are ₹5,00,000 and the corpus handed over is ₹1 crore. Under sections 6 and 10, each flat's share is its value divided by the total value.

Flat	Value in Declaration	Undivided share	Monthly share	Corpus share
A: 1,100 sq ft	₹1.10 crore	0.88%	₹4,400	₹88,000
B: 1,650 sq ft	₹1.65 crore	1.32%	₹6,600	₹1,32,000
C: 2,200 sq ft penthouse	₹2.75 crore	2.20%	₹11,000	₹2,20,000

For flat A: ₹1.10 crore ÷ ₹125 crore = 0.88%. Monthly: ₹5,00,000 × 0.88% = ₹4,400. Corpus: ₹1,00,00,000 × 0.88% = ₹88,000. Per square foot, A and B both pay ₹4 a month (₹4,400 ÷ 1,100; ₹6,600 ÷ 1,650), but the penthouse pays ₹5 (₹11,000 ÷ 2,200), because its value per square foot in the Declaration is higher. Under a per-square-foot rule it would pay ₹4 too. That is why the percentages in the Declaration matter.

Before you sign

• Read the sale agreement and deed for the words "Karnataka Apartment Ownership Act" or "co-operative society". The court gave weight to what the deeds said.
• Ask the builder for the draft Declaration and bye-laws, and check your flat's undivided-interest percentage.
• Buying resale? Ask the association's Secretary for a written statement of dues before paying the seller.
• If owners disagree about the form, a property lawyer can say which law fits your building.