For years, Amazon has been overcharging for sales tax in areas throughout San Diego County. Here’s where.

Amazon customers across San Diego County have been getting over-charged for sales tax on their purchases — sometimes for many years.

Days after The San Diego Union-Tribune reported that Amazon had wrongly charged residents of Del Mar Heights the sales tax rate for neighboring Del Mar, people in other areas around the county shared similar problems.

After reading the July 22 front-page story, residents living outside Vista and outside El Cajon carefully scrutinized their Amazon receipts and discovered similar overcharges.

And residents of another city of San Diego neighborhood that shares the same 92014 ZIP code with Del Mar — Del Mar Terrace — also discovered sales tax overcharges by Amazon.

But a notable difference is that the overcharges in other areas each date back several years, while the Del Mar Heights overcharges began May 1 and lasted less than two months.

That makes it likely that the amount of additional money Amazon erroneously collected with these is much larger than the amount collected erroneously in Del Mar Heights.

“This is even more egregious,” said Mary Allis Curran of Del Mar Terrace.

The newly discovered overcharges appear to be the result of Amazon making mistakes similar to the ones it made in Del Mar Heights, where customers should have been charged 7.75% because that’s the city of San Diego rate.

But those customers were instead charged 8.75%, the rate in the city of Del Mar, where voters approved a local one-cent sales tax surcharge in 2016.

Neighborhoods in unincorporated areas just outside the city of El Cajon should be charged 7.75%, because they are on county land and that’s the county rate.

But some residents there have been charged 8.25%, the rate within the city of El Cajon, whose voters approved a half-cent sales tax increase in 2008.

Unincorporated neighborhoods just outside the city of Vista should also be charged 7.75% because they are on county land — but some residents there have been charged 8.25%, which has been the rate in Vista ever since its voters approved a surcharge in 2006.

Vista resident Steve Nowak said reading about the Del Mar Heights mistakes “struck a nerve” and prompted him to review all his Amazon receipts going back 10 years — as far back as the company saves them before they get deleted.

He found that he had been charged the incorrect higher sales tax rate on every charge since then, estimating that he has been overcharged several hundred dollars.

And Nowak said he has many neighbors who have likely had the same thing happen to them.

“There are hundreds to thousands of properties in the same situation that border Vista on all sides that share ZIP codes with Vista — 92083 and 92084,” he said.

Nowak said he hopes Amazon will refund him, based on how it handled the Del Mar Heights overcharges. But he said he’s worried about purchases between 2013, when he moved to unincorporated Vista, and 2015 — the oldest receipts he has.

“I know I was overcharged from 2013 to 2015 too, but they delete those records on a 10-year interval,” Nowak said.

Susan Yoder lives near Mount Helix in an area that has El Cajon addresses but is not within the city of El Cajon.

“This is not just a Del Mar Heights issue but could affect thousands of people in San Diego County,” Yoder said by email. “I went back over my account, and it’s been since inception in 2022.”

Yoder said she suspects residents living near her in unincorporated areas bordering La Mesa are also getting overcharged, because the city of La Mesa has a sales tax rate of 8.5%. But to her surprise, each person she’s alerted in that area hasn’t been able to find any overcharges.

In another surprise, Yoder found that Amazon has been charging her husband — who lives at the same address — the correct sales tax rate, even as she’s been overcharged.

Nowak found the same thing. Amazon is charging his wife the correct sales tax rate, while he is overcharged.

Curran, the Del Mar Terrace resident, thinks her overcharges are substantial.

“I am guessing the overcharges will likely be over $1,000, though I have only done some rough math based on a sample number of statements,” Curran said. “I spot-checked, and everywhere it was 8.75%”

Curran guessed that the overcharging has been happening for at least five years, possibly as long as eight.

When the Union-Tribune alerted Amazon this week to the overcharges outside of Del Mar Heights, company officials agreed to look into them and possibly give the same kind of refunds they did in Del Mar Heights.

Spokesperson Richard Rocha said Friday that customer service reps would likely reach out to the affected customers by Saturday and let them know it’s looking into the overcharges and will issue refunds once it has enough information.

“While this appears to be a relatively limited issue, we take any issue seriously, and we’re going beyond the routine inspections of our systems to make sure we have it fixed,” Rocha said by email.

He didn’t say whether Amazon would be looking for other customers in the affected neighborhoods or would only focus on those customers referred by the Union-Tribune.

Rocha declined to say how common such errors are. But he did say the company has to navigate the complexities of thousands of tax jurisdictions nationwide.

Rocha also said Amazon does not keep any overcharged taxes and said the funds go to the appropriate government agencies.

With these overcharges, it’s not clear whether the extra money has gone to the governments where the affected residents actually live, which would be the county and city of San Diego, or to the cities where Amazon erroneously thought they lived — Del Mar, Vista and El Cajon.

Rocha said last week that Amazon would issue any refunds immediately and would not wait for government agencies to reimburse it.