There are myriad benefits to science departments that have a public engagement in science portfolio in addition to any recruitment of new undergraduates. These benefits are discussed in this paper and include: improving congruence between A level and first year undergraduate courses, training in science communication and the breaking down of barriers between the public and universities. All activity requires investment of personnel and incurs a financial cost. Small scale activities may be able to absorb this cost, but ultimately as the portfolio grows this will become an increasing drain on resources. Bristol ChemLabS Outreach has, from the very start, set out to be fully sustainable financially and in terms of personnel. A very important component is the full support of the senior management team. In this paper we discuss how we have achieved this.