Is your sump pump ready for winter rains?

Graphic image: how's your sump pump?Many residents in Los Gatos and nearby communities such as the Los Gatos mountain communities, Almaden Valley, Monte Sereno, Saratoga, the Cupertino foothills, etc. have sump pumps in their crawl space to pull off water that can accumulate below the house.

Water can get there for a variety of reasons, such as reverse grading (the soil should slope gently away from the house, but in some cases the slope is unfortunately toward the house), downspouts not being extended to carry roof water away from the structure, or even underground water bubbling up from below (that’s a problem for a drainage expert, not a do-it-yourself job). These situations often happen during periods of heavy rain.

Sump Pump Options

Like any other appliance, sump pumps come in all ranges of quality and performance from bare bones and portable to full of bells and whistles. They also get old and need maintenance from time to time, and they can fail. Some will turn on automatically, some must be switched on manually (assuming you are home to do it). Some run only on electricity, and will be no good to you during a power outage. Others come equipped with a battery backup.

If it’s been a long time since you have checked in on your sump pump, now is a good time to do it (or pay someone else to inspect it). Also check to see if the soil under the houses is graded or has channels to bring water to the sump pump. Also double check the downspouts to insure that they are carrying water away from your home / foundation.  The best time to inspect all of this is before you need it. (Anyone with air conditioning knows how hard it is to get a service call on a malfunctioning AC unit during a heat wave!)

Time to upgrade? I would suggest looking into sump pumps with battery backups so that it works even if the power goes off – that may be when you need it most. It would also be good to have one that can register water accumulating and turn on automatically.

 

Related reading:

Cracked Foundations, Adobe Clay Soils and Water in Silicon Valley (on the Valley of Heart’s Delight blog)

What is a cripple wall? (on popehandy.com)

What To Consider When Buying a Hillside Home in Silicon Valley

Water Table (on this site)

Water table

Have you ever wondered about the depth of the water table, or if the Belwood, Belgatos, Surmont and nearby neighborhoods have a high water table?

Today I checked the website of the Santa Clara Valley Water District, also known as Valley Water, for info on our water table’s depth. Our water table is more shallow than I expected, just 10 – 20 feet in our far east corner of Los Gatos!

I marked up a screenshot and linked the map to the source, so if you click on it you will find our neighborhood water depth info on the Valley Water site.

 

Map of groundwater depth in Belwood, Belgatos, Surmont, and nearby - water table

Click to visit the Valley Water site for groundwater depth

Ours is not the highest water table area or the smallest depth to first groundwater. The Edelen District, near Old Town Los Gatos, appears to have a depth of just 5-10′. It’s close to the Los Gatos Creek, so I imagine that may have something to do with it as well as seepage from the Santa Cruz Mountains.

Unsurprisingly, when I checked areas adjacent to the San Francisco Bay, the depth to first groundwater was between 0 and 5 feet.

What is a high water table? Does the Belwood area have a high water table?

Per Cotterill Civil Engineers:

A high water table area is defined as any area where the water table is within 1.8 metres, or 6 feet off the ground surface during the frost period up until the end of August or within 2.4 metres or 8 feet of the ground surface during the rest of the year.

It looks like the answer is no, we don’t have a high water table here generally. The depth to groundwater can change with heavy rains or with drought, so it is possible that at times water could percolate up in some circumstance. Since this is the average range for our area, any particular home or parcel may have something unique and different. You’d need to do some sort of testing to find out the actual depth to first groundwater for any specific address.

Other water issues

Many homes in this area do have water issues as there’s runoff from the hills, and sump pumps are commonly found in homes in our neighborhood. Water can travel downhill both above and below the surface, my drainage experts tell me. Not every property has the same level of challenges with managing surface or subsurface water. Foundation problems, which often are related to water issues, are not super uncommon, either, but most can be prevented by managing the flow of water away from the house, particularly from the downspouts. That’s low cost prevention but of the homes I see, probably only 10% have the water directed away from the home. Big mistake!

Curious about the groundwater depth beyond Santa Clara County? I found a list of the groundwater depth in various cities or towns in California which shows most of Los Gatos as having at least 10′.  Parts of Foster City and Redwood Shores (Redwood City) have less than 5′.

 

Related Reading

Where are the natural hazards in Los Gatos? (on the Live in Los Gatos Blog)

Interactive map to view risk of flooding from dam failure in Los Gatos (Live in Los Gatos Blog – our area does not appear to be in these zones)

What to consider when buying a hillside home in Silicon Valley (on the Valley of Heart’s Delight blog)

Water District removing 89 trees

The San Jose Water District announced that 89 trees will be removed near the water storage tanks in Belgatos Park. The work begins September 5th and should end by the 22nd, and work will run between 8am and 5pm.

Due to the heavy rains last year, some infrastructure needs repairs. With the water district removing 89 trees, there will be the ability to upgrade the water main.  The notice can be viewed below for those who missed it.

San Jose Water District letter regarding tree removal and work at the reservoir in Belgatos Park

San Jose Water District letter regarding tree removal and work at the reservoir in Belgatos Park

 

UPDATE: The older reservoirs have been replaced with new tanks. To read more about the replacement project, see the Belgatos Station Tank Project post on San Jose Water’s blog from 2018, the announcement of completion on SJW’s 2020 Infrastructure Update, or the contractor’s (brief) Belgatos Reservoirs project page.