Do you have a high water table?

How high is the water table at your property? (Why would you care?) In Los Gatos, like Almaden, Monte Sereno, Saratoga, and many other parts of Santa Clara County, there are pockets in which the water table, meaning groundwater, is quite high. This can come with some risks.

What are some of the potential issues with high ground water?

In some cases, that groundwater is at such a shallow level that there’s an actual spring with water bubbling up at times. This can happen particularly in times of heavy rainfall. Should it occur directly under your house and into your crawlspace, that would not be good. Water can cause havoc with foundations, so the standard advice from home inspectors and structural engineers is to divert water away from the house. In most cases, that means correct any faulty grading (the soil around the house should case any rainfall to be directed away from the house), to extend downspouts away from the home, etc. If you have a spring bring water up from underground, that is a whole different approach to the challenge.

Another concern with higher water tables is the possibility of environmental problems spreading from the site of a leaking underground storage tank to nearby neighbors (who would get stuck paying the cleanup). Underground plumes of water can carry chemicals from a spill site to some distance away. That’s why home buyers receive a natural and environmental report which includes contamination sites within one mile of the property they’re interested in purchasing.

How can you learn about your neighborhood’s water table?

It seems like experts have mapped just about everything, and one of those things does include the depth at which first groundwater can be found. Today I was curious about this question and was delighted to find a Valley Water map which lays out the various depths of the water table throughout much (but not all) of the Santa Clara Valley.

How shallow is the water in Los Gatos? Per this map, it appears that:

  • At the intersection of N Santa Cruz and Los Gatos-Saratoga Road, it’s 0 – 10 feet on the northwest corner and 10 – 20 feet on the southeast and southwest corner
  • Much of the Almond Grove area appears to have 0 – 10 ft depth for water
  • Old Town seems to have 10 – 20 feet
  • Los Gatos High and the Civic Center look to have 20 – 30 feet (interesting as there was a cleanup  at the Hotel Los Gatos and the high school from a leak at the Dry Cleaner next to the hotel a few years back)
  • The Town Park Plaza is in the 10 – 20 foot area

Click on the link to the Valley Water Open Data site and scroll around to see your part of town! (Unfortunately there are some big pockets missing.)

 

Image of the Valley Water open data map, including Los Gatos and Saratoga - click on image to visit the Valley Water website
Image of the Valley Water open data map, including Los Gatos and Saratoga – click on image to visit the Valley Water website