| Uncertainty | Description |
| Population increase | Subject to national and state policies |
| Performance and appropriateness of relatively new technologies | Project considered artificial wetlands and reverse osmosis as potential treatment process for sewage effluent, the operating characteristics of both being ill-defined |
| Degree of success in involving stakeholders in actions to alter water quality impacts | No legislative powers to direct land management practices of farmers and rural residential communities |
| Effectiveness and costs of Best Management Practices (BMP) in run-off controls | Local government had little experience of improved control mechanisms |
| Community expectations | Not clear if community is willing to pay for higher environmental standards in housing costs |
| Community acceptance | Use of recycled water for non-potable purposes untried |