Despite the large volumes of water that compose the water resources in the Amazon, there is still the difficulty of obtaining safe water for human consumption. In Santarém, only 45,34% of the population has access to treated water (Instituto Trata Brasil, 2016). In this scenario, some alternatives to water supply need to be evaluated, the rainwater is one of them. Thus, this paper presents a study of the potential for potable water savings in homes in the municipality of Santarém in Pará. For this were applied the methods proposed by Ghisi and Flowers , in which the relationship between rainfall, water demand and roof area for determining the potential of rainwater use in the studied municipality. The results indicate that the potential for potable water savings ranging between 10 and 100% The main conclusion of this research is that rainwater is a viable alternative to add to the conventional water supply. And that with the use of this feature, there would be significant savings in drinking water and consequently the preservation of water resources in the Amazon .

The urban area of the municipality of Abaetetuba/PA has only 66% of households served by the public system of water supply. This study aims to evaluate the rainwater utilization potential of this area, in order to contribute to the reduction of the deficit in attendance. The studies were carried out following the methodology in which three variables are critical: precipitation, drinking water demand and catchment area available, the latter variable obtained through statistical sampling, following the method. Thus: (1) Rain -obtained by HIDROWEB system of the National Water Agency (ANA) -there are two distinct periods: a rainy season (January to M ay) with 289 mm monthly average to 432 mm, and less rainy season (June to December), with monthly averages ranging from 67 mm to 203 mm .; (2) Demand -obtained by the National Sanitation Information System (SNIS 2010) -is 150 liters / person / day; and (3) catchment areas available -were measured from Google Earth system -ranging from 17 m2 to 300 m2, in which 47.9% has an area up to 80 m2. The potential obtained in the rainy season fully meets 74% of housing conditions investigated. In t he less rainy season, still meets 21% of the investigated housing conditions. It is concluded that the urban area of the municipality of Abaetetuba / PA has a significant potential for rainwater utilization, especially in the rainy season. And as for the least rainy season it is possible to book water accumulated at the end of the previous period, as is traditionally done in the Brazilian semiarid region. Thus the Amazon area uses its potential, given the adaptive strategies of other regions of Brazil.