Eighty years after their construction, the Stan Hywet Hall & Gardens' Manor House foundation, rainwater and surface drainage systems were in a dangerous state of disrepair that required immediate action to prevent further damage to the Manor House and gardens. An estate-wide needs assessment conducted in 1996 and an engineering study conducted in 1997 concluded that the severity of the deterioration of these systems endangered the future of more than 65% of this historic site.
The Manor House Water Management and Garden Restoration Project was a three-phase restoration that begun in May 2000 and completed in June 2010. The project included:
- The complete restoration of five Warren Manning signature gardens, including the re-establishment of the Great Garden
- Restoration of areas located at the south side of the property, including the upgrade of water lines for fire protection, the restoration of the London Plane Tree Allée and water management systems near the South Terrace
- The West Terrace Restoration - Complete removal of the Manor’s West Terrace, the re-establishment of two 100-gallon cisterns, and the subsequent restoration of the Japanese Garden