Please Join Us! Dewatering Regulations March 7th, 6 PM, City Hall

Palo Alto’s City Council will hold a special meeting on Tuesday, March 7th, 6 pm at City Hall, 285 Hamilton, to discuss and determine dewatering regulations for 2017 and 2018.    Please join us and let the City Council know that this issue matters to you.

City Staff is proposing to incorporate the 2016 dewatering guidelines as an ordinance in 2017, and to return to Council with a proposal for additional enhancements to the ordinance in 2018.  Continue reading

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Building basements without wasting water

City Council will review Staff’s recommendations for 2017 dewatering regulations on March 7th, 2017. Please join us for a special City Council meeting on Tuesday, March 7th at 6 pm (the City has changed the date several times; we will reconfirm date and  time when the agenda is final) at City Hall, 250 Hamilton and let City Council and Staff know that groundwater (all water) is important to you, and that proven alternative construction methods can be used to preserve this water. California is a land of recurrent drought. It is time for better stewardship of our groundwater – it supports our buildings and infrastructure, it’s our hedge against drought, part of our emergency water supply, and our children’s birthright.

In order to build a basement, the groundwater level needs to be lower than the basement’s foundation. When this level, the water table, is above the proposed basement’s foundation, it needs to be drawn down within the construction area; this is achieved by pumping the water out. In broad area dewatering (BAD), the method currently used, the groundwater level is drawn down not only at the construction site but hundreds of feet away from it (see diagram).

This is the equivalent of a localized drought for nearby neighbors and their properties. Depending on distance from dewatering site, type of soil, location, dewatering duration and other factors, broad area dewatering can affect nearby buildings, infrastructure and canopy. And, millions of gallons of groundwater are wasted. Last year’s average was 17.5 million gallons of groundwater per basement. For comparison, the amount of water required for fracking a well is between 2 and 10 million gallons.

Due to our collective efforts to bring this issue to the City’s attention, Staff is proposing for 2017 a pilot program that encourages using alternative construction methods for building basements in areas with high water tables. It is voluntary because Staff wants to see if there are any unintended consequences before recommending it be mandatory.

In alternative construction methods, also called local area dewatering (LAD), the use of cofferdams, sheet piles, cut-off or secant walls, etc., essentially limits the amount of groundwater that is pumped out for the underground construction (see diagram). The smaller amount of water pumped out via these methods is expected to be less than 10% of the amount pumped when broad area dewatering is used, and can then be percolated back to the aquifer or used beneficially such as for dust suppression, street cleaning, irrigation, etc. Local area dewatering not only limits the amount of water that is wasted but greatly reduces the risk of damage to neighboring properties, canopy and nearby infrastructure.

Why would anyone choose broad area dewatering when local area dewatering has much lower impacts on the built and natural environment? Under current regulations, the dewatering applicant doesn’t pay for either the groundwater that is pumped out or for the use of the storm drains, where this groundwater is placed. For applicants, this has made broad area dewatering economically more attractive than local area dewatering. Meanwhile, the costs are externalized to us, the taxpayers.

The wasting of this water is, however, not sustainable. It is time to protect our groundwater and its many benefits to our environment and us. Incentivizing local area dewatering and/or de-incentivizing broad area discharge can achieve this goal. Please show up on Mar. 7th and say that we want zero waste of our groundwater, a valuable community resource.

Thanks for your support!

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Policy and Services Committee endorses new rules intended to reduce groundwater waste

Thank you to all who wrote letters, showed up and spoke up for reducing groundwater waste for construction purposes at the Policy and Services Committee on Dec.14th.  Thanks to your support and advocacy, together we changed the game!

It’s clear that the Policy and Services Committee and City Staff now understand that wasting water is the issue, and that it’s not acceptable politically.  Or morally.  Or for any city that thinks of itself as sustainable.  There’s a clear consensus on the direction – the challenge is to figure out the best and fastest way to get to the goal in a cost-effective manner – and for an ordinance to become enacted. Next, Staff will prepare recommendations and bring to the full Council for approval, most likely 3/7/ 2017, but this date may change.  

One of the highlights of the many presentations to the Policy and Services Committee was this 2-minute animated video   made by Cate A, a precocious 8-year old in 3rd grade.  The message is powerful – please share with your friends.


We’re far from victory, Continue reading

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What Are Your Reasons?

We’ve been asked why we oppose dewatering. These are some of our reasons:

1. There are better ways to build basements that dramatically reduce the amount of water wasted.

2. Water Scarcity/Water Security

  • We’re in a drought.
  • We have a growing population.
  • Other cities (East Palo Alto, San Jose, etc.) are asking for a greater allocation from the San Francisco Public Utilities Commission, our common supplier.
  • The Bay Delta Water Quality Control Plan calls for 40% of unimpaired water flow from February to June.  Personally, we support this Plan which will result in healthier rivers and ecosystems but it will mean a lower water allocation for all.
  • “Groundwater is really our savings account: it’s the last resort, it’s what we have to use when there’s no precipitation” J. Koseff, Ph. D., Director of Stanford Woods Institute for the Environment.

dying river

3. Environment

  • Dewatering is an environmentally unsound practice – it reduces recharge to streams, rivers, wetlands and the deeper aquifer, it contributes to sea level rise, etc.
  • Groundwater supports our buildings and infrastructure and is a hedge against salt water intrusion and subsidence.
  • Contrary to current conventional wisdom, the shallow and deeper aquifers are connected (San Mateo County Groundwater Plan Meeting, 2016).

4. Safety

  • The deeper aquifer is the source of our emergency water supply.
  • The Santa Clara Valley Water District (SCVWD) needs to keep importing (scarce and ever more expensive) water to recharge our aquifer.  Recharging our aquifer avoids overdrafting and subsidence as happened in the 1960s.
  • With climate change and sea level rise, groundwater levels will rise also.  This study concludes that underground construction in which the current groundwater level is 4m [13 feet] or less will get flooded.  “We’re building tomorrow’s risk today”.

5. Community Resource

  • Groundwater is a community resource – less than 1% of groundwater pumped for basement construction comes from the property being dewatered, the rest comes from neighboring properties.
  • Residents want to know why they should conserve water when they see water gushing down the drains.
  • Dewatering does not adhere to the “Lead by example” and “designate a guardian of the future” principles in Palo Alto’s Sustainability/Climate Action Plan.
  • This groundwater is the birthright of our children and all residents, present and future.

These are some of our reasons – you may have others to share with our elected officials. Please send letters to For sample letters check out item 4 in our How to Get Involved page.

Thank you for caring about Palo Alto’s groundwater.


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Join Us Dec.14th, City Hall at 6 pm

Dear Supporters,

Many of you have expressed frustration and/or outrage at all the water gushing out of construction pipes into our storm drains, especially when trees are dying and we’re in a drought.

Palo Alto’s Policy and Services Committee will discuss dewatering regulations on Wednesday, Dec. 14th, 6pm at City Hall, 250 Hamilton Ave., Palo Alto. We need you and your children, friends and neighbors, to attend and show your support for better managing our groundwater, a finite community resource. We need to protect this water for long-term emergencies (extreme drought, main water pipeline failure, etc.) and for our children, grandchildren and all Palo Alto residents, present and future.


With your support, we are making progress; however, Staff’s proposal needs to be considerably strengthened in order to make meaningful reductions in the amount of groundwater pumped and dumped. City Staff’s proposal is available here.

Come join us and make your voice heard! Tell your neighbors! If you live in Palo Alto and need transportation to attend this meeting or if you have questions, please contact us at If you are absolutely unable to attend the Dec. 14th Policy and Services Committee meeting, please email the City Council at and make your views known. Not much will change unless together we make it happen.

We appreciate your support and look forward to seeing you at 6 pm on Dec. 14th at City Hall.

Save Palo Alto’s Groundwater!

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