Are we looking at a blue wave? Or is it a red wave? Is the silent majority going to rise up and make their voices heard at the ballot box? These are among the questions that are being considered by most campaigns going into November.

In California, Democrats in particular see an opportunity to increase their political dominance in the state -- specifically in traditionally Republican rural and agricultural districts like Congressional District 10 -- located in the San Joaquin Valley.

One only needs to look at how much money is pouring into the races to know just how badly the parties are trying to flip or defend their hold on a seat. Here are 5 of the most expensive US House races in California.

Note: All data in this article was provided by OpenSecrets.org. Numbers will be updated as new information is released.

1. Congressional District 22 - Nunes (I) v. Janz

It might seem jarring that over $10 million would be poured into a congressional race. It would make the election not only the most expensive House race in California, but high on the list nationally too. That is the situation in Congressional District 22.

OpenSecrets.org reports that at the end of the second quarter (the latest report featured), over $10 million had been raised by the candidates in the race. Incumbent US Rep. Devin Nunes raised over $7.3 million and spent over $4.4 million. His opponent, Democrat Andrew Janz, raised over $2.8 million and spent $1.7 million.

The amount Nunes has raised is interesting, because rarely does an incumbent feel the needs to raise so much money -- especially in a district that is rated so heavily in favor of the incumbent's party (R+8 in this case).

However, Democrats clearly see an opportunity to unseat the veteran congressman. A recent poll shows Janz -- a local prosecutor -- 6 points behind Nunes, but the same poll found the Democrat 12 points behind in July. Keep an eye on this race going into November.

Congressional District 22 is centered in the San Joaquin Valley, and includes cities like Clovis, Tulare, and the eastern part of Fresno.

2. Congressional District 39 - Cisneros v. Kim (Open Seat)

In January, Republican US Rep. Ed Royce announced his retirement from Congress -- one of the many retirement announcements that guarantee several new faces in the US House in 2019. Royce represents California Congressional District 39, which encompasses parts of Los Angeles, San Bernardino, and Orange counties.

The district also represents one of the best chances for Democrats to pick up another seat, so it no surprise that it has become the second-most expensive House race in California. According to the last report from OpenSecrets.org, nearly $6.8 million was raised by the two candidates in the race, as of the end of the second quarter.

The candidates are philanthropist Gil Cisneros, a Democrat, and Republican Young Kim, a former member of the State Assembly. Cisneros has raised and spent significantly more than his opponent, though has relied heavily on self-financing his campaign. Cisneros raised approximately $5.5 million, and spent $4.7 million. Meanwhile, Kim raised nearly $1.3 million and spent under $1 million.

3. Congressional District 23 - McCarthy (I) v. Matta

In terms of money raised, this race comes in at a close third. However, nearly all of the money raised in this election is going to the incumbent. US Rep. Kevin McCarthy raised nearly $6.6 million by the end of the second quarter and spent almost $4 million.

The district is located in the southern portion of the San Joaquin Valley, southern Sierra Nevada, the Tehachapi Mountains, and parts of the Mojave Desert. The district has a rating of R+14.

4. Congressional District 10 - Denham (I) v. Harder

California Congressional District 10 is another race politicos are watching closely. The election between US Rep. Jeff Denham and Democrat Josh Harder is rated as a toss up, and money is pouring in for both sides in an effort to give the campaigns they boost they need to win.

By the end of the second quarter, US Rep. Jeff Denham raised over $3.4 million, and spent nearly $1.4 million. The two biggest sources for these funds were large individual contributions and PAC money.

Meanwhile, Harder raised over $2.5 million, and spent over $1.4 million. According to OpenSecrets.org, much of these funds also came from large individual contributions, but also from small individual contributions as well.

The race is considered one of California's most competitive congressional seats. It has gotten heated, and even personal between the two candidates as the Republican congressman fights off an attempt by Democrats to flip the seat.

5. Congressional District 45 - Walters (I) v. Porter

US Rep. Mimi Walters is facing a November challenge from Democrat Katie Porter. Though the district has been consistently Republican, that hasn't stopped this from being one of the most expensive races in California .

The incumbent congresswoman raised over $2.9 million as of the last report, and spent nearly $1.8 million. Her opponent raised over $2 million and spent nearly $1.3 million.

Walters won re-election in 2016 with nearly 60% of the vote. She won in 2014 with 65% of the vote. Democrats would have a difficult time flipping this district.

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