The mechanisms of private-well groundwater contamination are uniquely complex, necessitating a multisector communicative approach to risk management, premised on behaviour promotion. In countries such as the Republic of Ireland (ROI), characterised by oftentimes high groundwater contamination risk and concurrently limited user awareness, incorporation of multidisciplinary, ‘expert-based’ knowledge may facilitate design of evidence-based, practical interventions. Expert interviews represent an efficient form of expert consultation, enabling ease of access to niche information and comparison of procedure, but remain under-utilised within the groundwater management literature. In response, the current study elicited opinion from 50 experts across four broad categories (communications, engineering/science, policy, and risk assessment) via a mixed-methods interview study. Semi-structured qualitative interviews were undertaken with experts from the ROI (n = 25) and European/North American countries (n = 25) and examined using thematic (qualitative) and bivariate statistical (quantitative) analyses. Experts noted financial cost, knowledge and social norms as primary barriers to adopting private-groundwater and other health risk-prevention behaviours. Lack of organisational knowledge as a communication barrier was significantly related to expert category (p = 0.034) and highlighted by a majority of communications experts (95%) compared to policy (75%), risk assessment (67%) and engineering/science (50%) experts. The most frequently suggested communication activities comprised events (24%), radio segments (22%), workshops (24%) and community meetings (30%), allied with family-oriented, discursive approaches to information delivery. Study findings may be used by both national (Irish) and international stakeholders in myriad hydrogeological contexts to develop educational outreach strategies and contribute to the existing groundwater-management-knowledge base.