Homebuying in Chino, Rancho Cucamonga, Ontario, Upland, and Fontana started 2019 by falling 8.7% as the county suffered the largest sales drop in over four years.

A large jump in the supply of homes — existing and new — available for purchase plus a significant dose of economic uncertainty led to San Bernardino County homebuying’s biggest chilling since the end of 2014. Here’s what my trusty spreadsheet told me when looking at house-hunting patterns at the neighborhood level — first-quarter pricing and 12 months of sales.

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ATTOM Data Solutions found these homebuying trends in these 15 major ZIP codes around western San Bernardino County — communities near the 10, 15 and 60 freeways — covered by the Inland Valley Daily Bulletin …

Purchases: Home sales for the 12 months ended March 31 totaled 7,383 vs. 8,089 a year earlier, a decline of 8.7%.

Who’s up: Prices increased in nine of this region’s ZIP codes as sales rose in two ZIPs.

Countywide: $311,000 median selling price, up 3.7% in a year. Prices rose in 44 of 61 San Bernardino County ZIP codes tracked. Sales of 24,592 vs. 26,834 a year earlier, a decline of 7.6% in a year. Sales rose in 10 of 61 ZIPs countywide.

How homebuying fared at the neighborhood level around Western San Bernardino County communities around the 10, 15 and 60 freeways — first quarter pricing and sales for the 12 months ended March 31 …

Alta Loma ZIP 91701: $519,500 median, up 2.9% in a year. Price rank in San Bernardino County? No. 5 of 61 ZIPs. Sales of 446 vs. 452 a year earlier, a decline of 1.3% in a year.

Chino 91708: $430,000 median, up 2.4% in a year. Price rank? No. 12 of 61. Sales of 105 vs. 118 a year earlier, a decline of 11.0% in a year.

Chino Hills 91709: $594,750 median, down 10.9% in a year. Price rank? No. 3 of 61. Sales of 732 vs. 818 a year earlier, a decline of 10.5% in a year.

Chino 91710: $474,000 median, down 0.2% in a year. Price rank? No. 6 of 61. Sales of 596 vs. 723 a year earlier, a decline of 17.6% in a year.

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Rancho Cucamonga 91730: $440,000 median, up 3.5% in a year. Price rank? No. 9 of 61. Sales of 607 vs. 683 a year earlier, a decline of 11.1% in a year.

Rancho Cucamonga 91737: $551,500 median, down 11.8% in a year. Price rank? No. 4 of 61. Sales of 275 vs. 342 a year earlier, a decline of 19.6% in a year.

Etiwanda 91739: $630,750 median, down 0.7% in a year. Price rank? No. 1 of 61. Sales of 457 vs. 507 a year earlier, a decline of 9.9% in a year.

Ontario 91761: $434,500 median, down 0.1% in a year. Price rank? No. 11 of 61. Sales of 381 vs. 363 a year earlier, a gain of 5.0% in a year.

Ontario 91762: $425,000 median, up 19.7% in a year. Price rank? No. 13 of 61. Sales of 621 vs. 502 a year earlier, a gain of 23.7% in a year.

Montclair 91763: $380,000 median, down 7.3% in a year. Price rank? No. 19 of 61. Sales of 200 vs. 247 a year earlier, a decline of 19.0% in a year.

Ontario 91764: $410,000 median, up 5.1% in a year. Price rank? No. 14 of 61. Sales of 332 vs. 420 a year earlier, a decline of 21.0% in a year.

Upland 91784: $626,500 median, down 3.6% in a year. Price rank? No. 2 of 61. Sales of 334 vs. 379 a year earlier, a decline of 11.9% in a year.

Upland 91786: $440,000 median, up 0.2% in a year. Price rank? No. 9 of 61. Sales of 411 vs. 468 a year earlier, a decline of 12.2% in a year.

Fontana 92335: $335,000 median, up 4.4% in a year. Price rank? No. 26 of 61. Sales of 501 vs. 558 a year earlier, a decline of 10.2% in a year.

Fontana 92336: $445,000 median, up 0.5% in a year. Price rank? No. 8 of 61. Sales of 1,029 vs. 1,108 a year earlier, a decline of 7.1% in a year.