The flat-rate pricing system was discontinued; instead, each household received a free monthly allowance of six kilolitres of water, and any consumption over that amount had to be pre-paid for.

Writing for the unanimous bench, Streicher agreed with the High Court that the prevailing free basic water allowance was insufficient to fulfil the state's obligations under section 27(1) of the Constitution.

The Supreme Court also found that the use of prepaid meter was unlawful in terms of the city's prevailing Water Service By-Laws.

This approach arose from O'Regan's finding that it was not appropriate for the courts to delineate the normative content of the section 27 right to water viz.

Thus turning to a reasonableness review, the court found that the City of Johannesburg's policy in Phiri was reasonable and lawful; both the six kilolitre free basic water allowance and the introduction of prepaid metres were compliant with section 27 of the Constitution, with the Water Services Act, 1997, and with the city's own bylaws.

[5] Although some commentators agreed with the court that its Mazibuko ruling followed from precedent in Grootboom and Treatment Action Campaign,[6] others viewed it as a retreat from the court's more progressive and activist stance in those cases;[7] Judge Dennis Davis viewed it as a deviation from Grootboom's "open ended and flexible" model of reasonableness review,[8] and Pierre de Vos described its interpretation of Treatment Action Campaign as "rather innovative" and "rather unconvincing".

[9] Indeed, Pieterse viewed Mazibuko – along with Residents of Joe Slovo Community v Thubelisha Homes and others – as part of a "second wave" of Constitutional Court jurisprudence on socioeconomic rights, defined by its increased concern with judicial deference to the political branches.