Water Wise Davis, a working group of Cool Davis, and Tree Davis, a Cool Davis partner, will host a 5th annual Greywater Showcase online via Zoom on Thursday, July 29, 2021, from 6:00pm to 7:30pm. This year’s theme is meeting tree watering needs with greywater, or, put another way, the connection between drought, trees, and greywater. Following presentations by Dawn Calciano, Don Shor, and Leslie Crenna, there will be time for Q&A and discussion. Larry Guenther, a Tree Davis board member, will welcome you, introduce our speakers, and move our program along.

Register for the online event today!

Are you a good candidate for a laundry greywater system? Throw your virtual ticket into the jar at the end of the program to win a FREE professional consultation and 1 of 2 laundry to landscape parts kits ($75 value for parts; professional consultation varies). Parts kits are sponsored by the City of Davis.

This event is FREE! Optional donation to Cool Davis to provide promotional and technical support for the event is appreciated.

Speaker Line Up

Dawn Calciano, City of Davis Conservation Coordinator, will give an update on drought and water resources and conservation in Davis. Dawn’s primary focus is on water conservation although she assists with other environmental resources programs as well in her role with the Environmental Resources Division. Prior to working for the City of Davis, Dawn worked as a Water Conservation Coordinator for the City of Woodland.

Don Shor is a Tree Davis board member and will speak about meeting tree watering needs with greywater. Don is a UC Davis alumnus and the owner of the Redwood Barn Nursery in Davis. Image credit httpswww.flickr.comphotosdavismediaaccess15762159279

Don Shor: Renowned plant expert Don Shor will speak about meeting tree watering needs with greywater. Don is a UC Davis alumnus and the owner of the Redwood Barn Nursery in Davis. He hosts the Davis Garden Show on 95.7 FM-KDRT, a local access radio station and is a lifetime active gardener, raising commercial almonds, pecans, walnuts, and mandarins on 13 acres in Solano County, with a large family orchard and vegetable garden. Don currently serves on the Tree Davis board.

Leslie Crenna  led a school-based sustainable community garden in the Sierra Foothills before arriving in Davis. She is a certified multiple subjects teacher and a lifelong writer, editor, and family historian. She has participated in trainings with Blue Barrel Systems and the American Rainwater Capture Systems Association. She is a Level 2 certified greywater designer and installer through Greywater Action. Leslie wears her Water Wise Davis and EcoAssistant hats at the Greywater Showcase. She is also the Cool Davis Communications Manager. Leslie will speak about the basics of greywater, water reuse, the potential for our community, and the two types of systems, plus a bit about trees and greywater.

Greywater Showcase program

Larry Guenther is a Tree Davis board member and the chair of the Davis Tree Commission, among many other community roles. His day job is with the Yolo County General Services Division. Courtesy photo.

6:00pm Larry Guenther Welcome, self-introduction, overview of program, rules of engagement, and speaker biographies

6:05pm Dawn Calciano Status of drought, water resources, and water conservation in Davis

6:20pm Don Shor Meeting tree watering needs with greywater

6:40pm Leslie Crenna Presentation on basics of greywater

7:10pm Q&A and discussion

7:20pm Wrap up: Bring up evaluation and begin

7:25pm Raffle: Are you a good candidate for greywater? Throw your virtual ticket into the jar (raise your Zoom hand) for a FREE professional consultation and one of two laundry-to-landscape greywater parts kits courtesy the City of Davis and EcoAssistant.

7:30pm End

Register for the online event today!

For more information, email Leslie Crenna at lesliecrenna@gmail.com. Water Wise Davis supports wise water policy, and water conservation, reuse, and capture in the City of Davis and is a working group of Cool Davis. This event is supported by the City of Davis.

Amber Crenna-Armstrong reveals a first-year maturing nectarine fruit, grown from weekly clothes washing greywater. Photo courtesy Leslie Crenna.


Laundry greywater system parts kits will be given away to participants who are good candidates for a home system — a $75 value in materials alone! Each kit comes with a complimentary professional consultation as well (costs vary by provider)! Courtesy photo.


Amber Crenna-Armstrong shows off two very happy first year fruit trees after their first year Solstice prune, one pomegranate and one nectarine, feeding on weekly clothes washing greywater. No supplemental irrigation system watering has occurred since they were first planted in December 2020. Photo courtesy Leslie Crenna.

Water scarcity and extreme heat in California

Event host Larry Guenther pointed out at the recent City of Davis CAAP Resilience and Equity workshop that “NOAA has officially stated that the average annual temperature has already increased 1°C across the entire US. Estimates are that an increase in 1°C will reduce the Sierra snowpack by 50%. This completely changes California’s water paradigm.”

According to drought.gov, Yolo County is experiencing the 15th driest year in 127 years of monitoring at 6.65 inches less than normal. One hundred percent of Yolo County is in the Extreme Drought category when livestock need supplemental feed, fruit trees bud early, producers irrigate in the winter, fire season is year-round, burn bans are put in place, and supply is inadequate for agriculture, wildlife, and urban needs.

The next and highest level D4 is termed Exceptional Drought when fields are left fallow, fire activity is extensive, wildlife death is widespread, and algae blooms appear. The drought.gov social vulnerability index indicates that Yolo County ranks .68, within the third, most vulnerable of four ranges (.5 to .75) (with .75 to 1.0 as the highest).

According to water.ca.gov, “natural flow in key Sierra Nevada watersheds this year has been tracking amounts experienced in the severe drought years of 2014 and 2015, although the April 1 snowpack of 59 percent of average surpassed that of the very dry and warm water years of 2014 and 2015, when record lows of 25 percent and five percent of average were set.

Reflecting the low streamflows, storage in the largest northern California reservoirs is also well below average and allocations from the State Water Project and federal Central Valley Project are low. … California is experiencing the expected transition to drier conditions with more erratic precipitation conditions predicted by climate models.”

Governor Newsom proclaimed a State of Emergency in Mendocino and Sonoma counties as part of the Russian River Watershed April 21, 2021, including a directive to develop a California Drought Monitor by December 31, 2021 (current drought monitor is at the federal level).

The National Weather Service issued an excessive heat warning Thursday, June 3, for the Central Sacramento Valley and several other regions. On Tuesday, June 1, several heat records were set including 105 at the Sacramento Executive Airport and 106 in Downtown Sacramento.

Needless to say, drought has returned and extreme heat is on the rise.

Greywater in California

One measure to combat extreme heat and water scarcity is greywater.

In California, greywater is defined as water collected from washing machines, sinks (excluding the kitchen sink), showers, and bathtubs that can be used for landscape irrigation. Greywater systems may help reduce household water usage especially in summer by reducing the use of potable water for outdoor irrigation. City and state level code and ordinance uses a different spelling: “graywater.”

The easiest and permit free system is a “laundry to landscape” system that directs drainage water from your clothes washing machine to your landscape. The next level requires a bit more commitment of time and resources: a “branched drain” system directs drainage water from showers, bathroom sinks, and tubs to your landscape and requires a permit. Hopefully, indoor reuse systems will also be represented at the showcase.

City of Davis Advice: Supplemental Summer Tree Watering

Ready or not, the summer months are upon us and that means dry and hot weather. This not only affects us, but also the trees planted at our homes and in our community. The City’s Urban Forest Division works hard to ensure a healthy tree canopy by managing more than 16,000 trees. However, we can’t do it alone! Proper and sufficient watering of trees is vital to the health of our tree canopy.
Is your tree still young and staked?
  • Give it 10 gallons of water once a week
  • Once the roots are established and staking is no longer needed, weekly water is no longer necessary.
Is your tree mature?
  • Supplemental water is only needed once a month during hot and dry weather, twice a month during prolonged heat waves.
  • Drip or flood irrigation over the critical root zone is best.
  • Avoid overhead spray, if possible. If overhead spray is the only option, do not allow water to spray the tree trunk!
The City’s Urban Forest Division has a number of helpful videos on watering trees:
Find more tips on caring for your trees at City of Davis Urban Forestry.




2019 Ca Plumbing Code: Alternative Water Sources for Non-Potable Applications

City of Davis Water Resources and Conservation web page

State of Emergency Proclamation

Earth Day 2020 – CNRA Science TED Talks: Julia Ekstrom

Save Our Water

Sustainable Groundwater Management Act