Santa Clara County Zoning - R3H

[Jonathan Pflueger]

Hello BP!

Does anyone know what the zoning code R3H means for the County of Santa Clara, specifically the H part? I understand the code R3 to mean - 

1. R3 Multi-Family Residential. The purpose of the Multi-Family Residential district, also known as the R3 district, is to provide space for multiple family residential development commonly found in an urban environment. The R3 district is intended for intensive residential uses at readily accessible urban locations (City of Santa Clara Zoning Ordinance)

But I cannot find out what the H means in R3H? I am looking at a SFH that I would like to possibly convert to multi or add additional units but I am having a hard time finding out exactly what the zinging is. Any insights would be greatly appreciated.