By definition ordinances are laws enacted by a municipal body that are not already covered by state or federal laws.
Since the Municipal Authorities Act of 2001 provides for the right of a municipality to takeover an authority's assets it would appear that a referendum to create a law that would prevent the sale of the assets of the water department of the Hazleton City Authority would contravene that law. Keep in mind that Hazleton City Council has yet to adopt a resolution or ordinance authorizing the sale of those assets therefore a referendum even if applicable would, at this point, seem premature. Any law enacted by referendum to supercede those powers granted by state law may end up being invalid.
In the case of Erie cited in the Referendum Handbook the voters stopped Erie from selling its water company to an authority. If one looks closely that sale is not covered under any state law per se. Therefore its application in this case is slightly different. Takeover of authority assets are covered by the Municipal Authorities Act, therefore, a signifcant legal question remains whether the referendum mechanism is a viable remedy for those opposed to the sale.
The bigger probelm comes from the opposition itself. Certain persons are self-proclaimed governement watchdogs, yet they want to use the Authority's solicitor as their own private attorney. Those in opposition need to seek outside counsel and prove that they are on legal ground, not just copy and paste something from the referendum handbook to validate their claims.