In the case of owning a particular authorized capture * (well, hole), you should ensure that there is no interconnection with the network. Only in this way it is ensured that there are no non-potable water taps for supply for human consumption.
We recall that the non-potable water consumption places, not only to your health at risk, as it represents a public health problem for all users.
Please note that the connection to the public network is a legal obligation and that, as stipulated in the Decree-Law 194/2009 of 20 August and Decree-Law 226-A/2007 of 31 May, given the existence of public water supply and sanitation, available less than twenty metres from the boundary of the property, should be abandoned private solutions to water supply for human consumption or drainage.
According to the stipulated in the legislation referred to above, the failure to comply with the binding obligation constitutes a misdemeanour punishable by a fine, of up to 3 740 €, for individual and collective 44 890 € for person.
Blend water from a private funding with public water can contaminate not only the network of your dwelling as the entire network.
Always keep in mind that particular catchment water, even to present good aspect or pleasant taste, is unfit for human consumption, since it may contain microorganisms or substances harmful to your health.
* All private funding must comply with the legislation in force and are authorised by the Portuguese Environment Agency.