The level at which tariffs are set for services can be an extremely political issue. Historically, utility tariffs may have been used to subsidize certain elements of society, specific industries or public sector entities. More often, public utilities are subsidized and tariffs are not charged, charged at very low rates or not collected. PPP may necessitate formal arrangements with the project company for government subsidies or financing, particularly where the government is not willing to put tariffs up to profitable levels or where substantial investment in capital works is needed or desired. Though challenging, this can be a healthy transition for the utility, formalizing the subsidy for the water sector and rendering transparent the burden on the public purse represented by artificially low tariffs. While this will be of particular concern for the Fee vs Tariff paradigm discussed below, it is also important for setting tariffs and any tendency to politicize this function can complicate the project company's task of invoicing consumers and collecting tariffs.