Postcards & Passports

A Day at Diamond Valley Lake

This post was most recently updated on July 9th, 2019

I first heard about Diamond Valley Lake about 14 years ago, when construction on the dams was completed and it was filled with water. I thought, “Cool! A new lake!” But it was only recently, on a hosted trip to San Jacinto Valley, that I learned what makes it so important.

Diamond Valley Lake

View of lake during the early morning

Diamond Valley Lake is a man-made lake 85 miles north of San Diego and 90 miles southeast of Los Angeles. It’s also a drinking water reservoir. It actually holds enough water for a six-month supply for 19 million customers in southern California. It was always intended that Diamond Valley Lake provide recreation as well — boating and fishing, plus hiking, horseback riding, running, and cycling on its shoreline trails. But I don’t think anyone expected Max the Mastodon. And that is what really put Diamond Valley Lake in the news!

Who is Max the Mastodon?

During excavation for the reservoir, prehistoric bones and skeletons were found. Among these were the remains of mastodons, mammoth, camel, sloth, dire wolf, and long-horned bison. In fact, paleontologists uncovered millions of fossils, and this area is now unofficially referred to as the ‘Valley of the Mastodons’. The fossil finds here rival that of the La Brea Tarpits in Los Angeles.

Diamond Valley LakeSo…who is Max the Mastodon? Max was the name given to the largest of the mastodon skeletons found while creating Diamond Valley Lake. And Max is now the mascot for the Western Science Center, built to showcase and preserve the many fossils found.

Western Science Center

3D map of Diamond Valley Lake

Western Science Center

When Max the Mastodon and all the other fossil remains were found, the Metropolitan Water District decided to build the Western Science Center. This is more than just a fossil display. The center has exhibits about the native people who lived in this area as well as traveling exhibits from Smithsonian.

While I was there, they had an H20 display that was very interesting. It described water distribution and water use with eye-catching art and graphics. There was also an exhibit called Pollinators.

But the highlight is the main exhibit hall, where you can see actual fossil bones under glass. In fact, you can even walk over some of them! And reproductions of the fossils are arranged in full scale so you can imagine what Max and other creatures looked like.

There’s also a working lab, where you can watch paleontologists working on actual fossils.

Diamond Valley Lake

Fossil Cleaning lab work

There are classes and lectures and special events going on at the Western Science Center. For more information, please check out their website. On Saturdays, for example, you can attend Science Saturdays, which is always free and includes hands-on activities and games for kids. And rumor has it there will soon be a stuffed Max the Mastodon available for sale in their gift shop!

The other cool thing about the Western Science Center is that it’s also a science-focused charter school for junior high and high school students. You can see their simulated dig site where they learn how to be archaeologists or paleontologists. This school is so popular that there’s quite a waiting list to enroll!

Diamond Valley Lake Visitor Center

If you’re traveling to Diamond Valley Lake on a weekend, you might wish to visit the Diamond Valley Lake Visitor Center. Located on the Western Science Center campus, it houses fossils and shows videos about the creation of the lake. You can climb inside a 12-ft wide piece of water pipe or see a 10-ft wide tire taken from the smallest dump truck used for the project. Native American artifacts are also on display.

Diamond Valley Lake Aquatic Center

Within sight of the Western Science Center is the Diamond Valley Lake Aquatic Center. It has a heated 25-yard outdoor pool with a water slide, zero depth entry with water fountain sprayers and activity toys for small children. When I saw the aquatic center, I figured it would be a huge hit with the kids and a great way to cool off on hot and dry summer days. I plan to return and introduce my grandchildren!

Diamond Valley Lake Aquatic Center

Aquatic Center

The aquatic center is actually part of the larger Diamond Valley Lake Community Park, which includes athletic fields, tennis and basketball courts, fitness trails, restrooms, and picnic tables.

Diamond Valley Lake

Oh, that’s right! And then there’s the lake…

When I learned we’d be going on a boat tour of the lake, I was pretty excited. The weather couldn’t have been better on this beautiful October morning. Metropolitan Water District representatives accompanied us and gave us all kinds of interesting information about the lake.

There is a small marina at the east end of the lake, where fishing boats and pontoons are available for rent. The boat launch was recently extended to allow access to the lake when water levels are down.The lake is stocked with rainbow trout, catfish, black bass, bluegill, and sunfish…and the fishing is pretty good here.

Diamond Valley Lake is not fed by any streams. All of its water comes from the Colorado River Aqueduct and is pumped into the lake. Water also comes from the California State Water Project, which draws water from Silverwood Lake. Because this is a drinking water reservoir, the decision was made to keep it a non-body-contact lake. Residents were disappointed in the no-swimming policy, but it makes it a lot easier to filter the water for purity. The Aquatic Center was built in response to the need for swimming recreation near the lake.

I was fascinated with the scale of the lake — three separate dams, the longest of which is just over 2 miles long! The reservoir is built to hold 800,000 acre-feet of water. You can visualize this by imagining the size of a football field one foot deep with water. Times 800,000! There is more water here than at Lake Havasu! More detailed information about the construction and all things related to the lake can be found here.

It was also smart planning a location that provided its own materials. The bedrock walls of the canyon were used to construct the dams.

Diamond Valley Lake quarry

This is where most of the material for the dam was taken from

It’s hard to describe just how beautiful this lake is, and my photos don’t really do it justice. I hope you’re able to make a trip to Diamond Valley Lake to see it for yourself!

Diamond Valley Lake

So serene

Time for a treat?

At some point in your day, you’re going to want something cool to beat the heat. La Michoacana treated us to one of their amazing Mexican ice cream desserts. Here you can find fruit bars, ice creams, sorbets, floats, and much more. Everything is handmade on site, so it’s fresh. (The pina collada ice cream had actual coconut flakes in it–so good and so refreshing!). Honestly, I was amazed at how reasonable the prices are.

Suggested Itinerary:

I would go to the lake first, in the early hours of the day, before it gets too hot. Walk the trails or better yet, rent a boat for the best views of the lake. Then I would visit the Western Science Center and the Diamond Valley Lake Visitor Center. You could enjoy a picnic lunch at the Diamond Valley Lake Community Park (or drive a few miles to pick up lunch in Hemet) and then enjoy an hour or so at the Aquatic Park. Now your kids will be ready to sit quietly in the car for a trip back home. I am positive you will love your day at Diamond Valley Lake!

Staying Overnight?

If you decide an overnight stay will give you more time to explore the Diamond Valley Lake area, I can recommend the Best Western Diamond Valley Inn. Rooms for four start at only $101 with the AAA discount, and a full breakfast is complimentary, along with free parking and wi-fi. Best Western Diamond Valley Inn is only 5 1/2 miles from Diamond Valley Lake and is close to restaurants, shopping, and other area attractions, too. You can also also enjoy strolling through downtown Hemet. Did you know it was voted one of the top ten ‘Most Walkable’ cities in southern California? Read my post on downtown Hemet for more information.


  • The Western Science Center, 2345 Searl Parkway, is open 10 am – 5 pm Tuesday through Sunday. Admission is $8/adults, $6.50/seniors and students 13-22, $6.00/youth (5-12), and children 4 and under (and military) are free. If you’ll take your family more than once within a year, the family pass is a better deal. It’s only $60 for two adults and three children, and includes discounts and member-only events.
  • The Diamond Valley Lake Visitor Center, 2325 Searl Parkway, is open Saturdays and Sundays, from 10 am to 4 pm. Admission is free.
  • Diamond Valley Lake Aquatic Center, at 1801 Angler Ave, is open only during the summers. Fees are low, $2/$3 for 2 1/2 hour sessions and $6/$7 for 5-hour sessions
  • There is a $9 fee per vehicle to enter and park at Diamond Valley Lake. If you want to hike the trails, there is a $2 lakeview trail fee per person. Boat rental fees range from $25/hr for a fishing boat to $90/hr for a deluxe pontoon boat.
  • La Michoacana is located at 3220 W. Florida Ave in Hemet. It is only 3.8 miles from the Diamond Valley Lake Aquatic Center or Western Science Center.
  • Best Western Diamond Valley Inn is located at 3510 W Florida Ave in Hemet. It is a boutique hotel with 66 rooms and is AAA approved.

*I would like to thank San Jacinto Valley, Western Science Center, and Metropolitan Water District for hosting me on my Diamond Valley Lake exploration. And thanks to Best Western and La Michoacana for feeding me well!

I’ve partnered with GPSmyCity, and this article can now be downloaded free. You may read it offline, or upgrade for a small fee to receive the article with GPS coordinates embedded. You won’t need the internet or data to be guided through the Diamond Lake area! I will receive a few cents commission, which helps to keep this blog going–thank you!

Diamond Valley Lake


15 thoughts on “A Day at Diamond Valley Lake

    1. Tami Post author

      Yes, Heather, it does get quite warm in the summer months…in the 90’s from June through September. Diamond Valley Lake and the surrounding San Jacinto Valley make a perfect snowbird location because the average day temperatures are 68 degrees December-February!

  1. Vyjay

    The Diamond Valley lake looks beautiful. But yes, more fascinating is the association with its findings. I am sure the place makes for an interesting experience.

    1. Tami Post author

      Definitely. I’ll be writing about other activities in the San Jacinto Valley area soon. It’s a wealth of resources!

  2. Tonya

    I really loved exploring San Jacinto Valley and that boat ride was so relaxing! The area is full of such interesting history- like how they found Max the Mastodon! I can’t wait to visit again. And it was great meeting you!

    1. Tami Post author

      Thanks, Tonya! Likewise. It was a wonderful experience, and I’m already trying to figure out when I’m heading back!

  3. Vicky and Buddy

    Omg, the fact that there is a working lab and you can watch the paleontologists working on fossils is so cool! I love checking out sites like this. Have you heard of The Mammoth Site in South Dakota? There are also a ton of fossils there and they’re still digging them up. If you get a chance to visit, I highly recommend it.

  4. John

    What a beautiful lake! The contractors certainly did a remarkable job in building this.

    There seems to be something for everyone – from the student of anthropology to the family with children. This would seem like a great 1-2 day diversion on a Southern California itinerary.

  5. Ted Morgan

    Tami, thank you for visiting our valley. We love it here. Not having any freeways running through the valley keeps the small-town feel!

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