The digital sector does not have a neglectable footprint, contributing to global climate change and overcommitment of planetary boundaries. To face environmental challenges, digital services could provide help and even mitigate other sector environmental impact. But, as the assessment of the environmental impacts of digital services remains difficult, digital services are still uncertain solutions. Global assessments of the digital sector already exist but are still often uncompleted, limited to carbon emission, use phase of the equipment and are made at a too large scale to be applicable. As digital services rely on highly mutualized equipment and infrastructure, it is difficult to assess the cost of a single service. In this paper, we propose a methodology to calculate the complete environmental impact of a service. We take a service provider's perspective on how, and with what data from service hosting, to calculate and reduce the service footprint. From a host point of view, we distribute the footprint between the services, allowing to consider precisely the impacts. With such data on the environmental impacts of the hosted services, we propose strategies to prioritize optimization effort and decommissioning policies.