99328 ZIP Code — Dayton, WA

Columbia County, Washington

ZIP code 99328 is located in Dayton, Washington, within Columbia County. It covers approximately 657.29 square miles and serves a population of 3,669 residents. This is a standard ZIP code in the Pacific (PT) timezone, served by area code 509.

About ZIP code 99328

The housing stock consists of predominantly single-family detached homes. Most homes were built in the pre-1940, giving the area an established character. Median home value is $224,000. Owner-occupancy is high at 76%, well above the national average.

Median household income is $69,355. 47% of households receive Social Security income, suggesting a notable retiree or disability population.

The dominant occupation class is management, business, and professional, with education and healthcare as the leading industry. The average commute of 19 minutes is near the national average.

Educational attainment is near the national average, with 26% of residents holding a bachelor's degree or higher.

Notable community characteristics include a notable veteran presence at 13% of civilians, above the national average of 7%.

Overall, ZIP code 99328 reflects a community defined by a strong veteran community, high homeownership, and a significant Social Security-dependent population.

3,669

population

657.29

sq mi land

Standard

ZIP type

Pacific (PT)

timezone

99328 ZIP code map

Cities in ZIP code 99328

Below are the cities the US Postal Service accepts for ZIP code 99328. Using any city not on this list may result in mail delivery delays.

City	Status
Dayton	Preferred

Nearby ZIP codes

99361 Waitsburg (13.2 mi) 99347 Pomeroy (15.8 mi) 99329 Dixie (18.7 mi)

Demographics updated 05/2026

Population
Total population	3,669
Population density	6 / sq mi
State FIPS	53
County FIPS	013

Geography
Land area	657.29 sq mi
Water area	3.45 sq mi
Latitude	46.3118
Longitude	-117.8730
Timezone	Pacific (PT)
Area code	509

Total population by age

Gender

Race & ethnicity

Economics updated 05/2026

Household income

Income range	This ZIP	County avg	State avg
Under $50k	33.4%	35.2%	31.7%
$50k – $100k	39.3%	37.8%	30.6%
$100k – $200k	21.1%	20.7%	27.1%
Over $200k	6.3%	6.2%	10.6%

Demographics & statistics

3,669

Population

People per sq mi

50.5

Median age

$69,355

Median household income

$41,467

Per capita income

$224,000

Median home value

$852

Median monthly rent

76.4%

Home ownership

9.0%

Poverty rate

3.2%

Unemployment

1,597

Housing units

25.7%

Bachelor's or higher

Age distribution

Male Female

Under 5

113

5–9

113

10–14

15–19

112

20–24

112

135

25–34

136

200

35–44

201

213

45–54

213

152

55–59

153

159

60–64

160

314

65–74

314

178

75–84

179

85+

← Male

Female →

Age summary

Group	Count	%
Under 18	637	17.4%
18 and over	3,032	82.6%
65 and over	1,055	28.8%
Median age	50.5 years

Race & ethnicity

White 73.6%

Two or more races 11.6%

Hispanic or Latino 9.8%

Other race 4.3%

Black or African American 0.6%

American Indian / Alaska Native 0.1%

Group	Count	%
White	2,992	73.6%
Two or more races	470	11.6%
Hispanic or Latino	397	9.8%
Other race	175	4.3%
Black or African American	24	0.6%
American Indian / Alaska Native	6	0.1%

Household income

Income range	This ZIP	County avg	State avg
Under $50k	33.4%	35.2%	31.7%
$50k – $100k	39.3%	37.8%	30.6%
$100k – $200k	21.1%	20.7%	27.1%
Over $200k	6.3%	6.2%	10.6%

Under $10k 3.7%

$10k–$15k 7.6%

$15k–$25k 7.4%

$25k–$35k 5.6%

$35k–$50k 9.0%

$50k–$75k 20.4%

$75k–$100k 14.7%

$100k–$150k 20.9%

$150k–$200k 6.6%

$200k+ 4.1%

Range	% of households
Under $10k	3.7%
$10k–$15k	7.6%
$15k–$25k	7.4%
$25k–$35k	5.6%
$35k–$50k	9.0%
$50k–$75k	20.4%
$75k–$100k	14.7%
$100k–$150k	20.9%
$150k–$200k	6.6%
$200k+	4.1%
Median income	$69,355

Housing

Home values

Under $50k 6.4%

$50k–$100k 9.4%

$100k–$150k 12.9%

$150k–$200k 16.5%

$200k–$300k 18.4%

$300k–$500k 30.4%

$500k–$1M 2.9%

$1M+ 3.2%

Housing overview

Metric	Value
Median home value	$224,000
Median rent / month	$852
Owner occupied	76.4%
Renter occupied	23.6%
Vacant	17.1%
Single-family detached	87.2%
Large apartment buildings	0.0%
Mobile homes	4.1%
Median rooms	5.7
Avg household size (owned)	2.18

Year built

Era	%
2020 or later	0.0%
2010–2019	6.7%
2000–2009	6.5%
1990–1999	4.0%
1980–1989	2.3%
1970–1979	11.3%
1960–1969	6.2%
1950–1959	9.7%
1940–1949	13.1%
1939 or earlier	40.1%

Bedrooms

Size	% of units
No bedroom (studio)	2.4%
1 bedroom	12.3%
2 bedrooms	27.9%
3 bedrooms	35.5%
4 bedrooms	15.8%
5+ bedrooms	6.0%

Vehicles per household

Vehicles	% of households
No vehicle	3.5%
1 vehicle	26.1%
2 vehicles	32.8%
3 or more	37.5%

Heating fuel

Fuel type	%
Utility gas	3.4%
Electricity	74.3%
Propane / LP gas	1.4%
Fuel oil	8.4%
Wood	11.8%

Households & families

Household type	Count	%
Married-couple family	808	49.1%
Cohabiting couple	110	6.7%
Male householder, no spouse	284	17.2%
Female householder, no spouse	445	27.0%
Households with children under 18	390	23.7%
Households with seniors (65+)	703	42.7%
Average household size	2.18

Marital status

Status	Male	Female
Never married	25.5%	24.8%
Married	59.0%	48.9%
Separated	0.0%	0.1%
Widowed	3.4%	14.2%
Divorced	12.1%	11.9%

Education

Less than 9th grade 3.5%

Some HS, no diploma 7.3%

HS graduate 20.2%

Some college, no degree 28.8%

Associate's degree 14.4%

Bachelor's degree 14.8%

Graduate / professional 11.0%

Metric	%
HS diploma or higher	89.2%
Bachelor's or higher	25.7%

School enrollment (ages 3–17)

Type	Count	%
Nursery / preschool	16	2.6%
Kindergarten	45	7.3%
Elementary school	293	47.8%
High school	89	14.5%
College / grad school	170	27.7%

Employment

Industry of employment

Education & healthcare 28.3%

Retail trade 14.3%

Agriculture & mining 10.8%

Manufacturing 9.7%

Public administration 8.4%

Construction 7.1%

Professional & management 7.0%

Transportation & utilities 4.8%

Other services 4.3%

Finance & real estate 2.5%

Arts, food & hospitality 1.7%

Wholesale trade 0.7%

Information 0.3%

Occupation

Category	%
Management, business & arts	33.6%
Service	17.3%
Sales & office	18.8%
Natural resources & construction	16.9%
Production & transportation	13.4%

Employment type

Type	%
Private sector	62.1%
Government	31.0%
Self-employed	6.8%
Unpaid family workers	0.0%

Commute

Method	%
Drive alone	73.6%
Carpool	10.9%
Public transit	0.0%
Walk	6.7%
Work from home	5.3%
Other means	3.6%
Avg commute (minutes)	19.1

Poverty

All people 9.0%

Under 18 years 6.3%

18 and over 9.6%

Married-couple families 4.1%

Female-led households 12.5%

Income support

Source	% of households
Social Security	47.0%
Retirement income	27.6%
Supplemental Security	5.2%
Cash public assistance	1.1%
Food stamps / SNAP	12.7%

Health indicators

Condition	%
Obesity	33.9%
High blood pressure	34.6%
High cholesterol	36.2%
Diabetes	11.4%
Heart disease	8.5%
Stroke	4.0%
Asthma	10.9%
Arthritis	30.1%
Kidney disease	3.7%
Pulmonary disease	8.4%
Cancer	9.0%

Behavior / access	%
Smoking	16.2%
Binge drinking	14.4%
No physical activity	20.6%
Less than 7 hrs sleep	27.2%
Depression	24.9%
Fair or poor health	16.1%
Poor mental health	14.4%
Poor physical health	12.6%
No health insurance	10.4%
Visited doctor (checkup)	70.9%
Visited dentist	64.2%
Cholesterol screening	90.2%
Teeth loss	12.4%

Veterans & disability

Veterans	Count	%
Civilian veterans	393	13.0%

Disability	%
Any disability	21.8%
Under 18	6.0%
18–64 years	17.5%
65 and over	39.8%

Health insurance coverage

Type	%
Private insurance	59.6%
Public insurance	52.8%
No insurance	8.6%
Uninsured under 19	0.9%

Language & origin

Language spoken at home (age 5+)

Language	Count	%
English only	3,499	95.4%
Spanish	199	5.7%
Other Indo-European	168	4.8%
Asian & Pacific Islander	6	0.2%
Other languages	25	0.7%

Place of birth & citizenship

Origin	Count	%
Native born (US)	3,526	96.1%
Born in same state	3,512	95.7%
Born in different state	2,285	62.3%
Foreign born	14	0.4%
Naturalized citizen	143	3.9%
Not a US citizen	43	30.1%

Ancestry

Ancestry	Count	%
French	575	15.7%
Italian	413	11.3%
Arab	160	4.4%
English	120	3.3%
Polish	87	2.4%

Ancestry	Count	%
Dutch	59	1.6%
German	18	0.5%
Irish	14	0.4%
Norwegian	6	0.2%

Technology access

Metric	% of households
Computer access	44.9%
Internet access	94.0%

Source: U.S. Census Bureau, American Community Survey 2025 estimates.

Frequently asked questions about ZIP code 99328

What city is ZIP code 99328 in?

ZIP code 99328 is primarily assigned to Dayton, Washington.

What county is ZIP code 99328 in?

ZIP code 99328 falls within Columbia County, Washington.

Does ZIP code 99328 have an older population?

29% of residents in ZIP code 99328 are 65 or older, above the national average of ~17%.

Does ZIP code 99328 have a large retiree population?

47% of households in ZIP code 99328 receive Social Security income, suggesting a significant retiree or disability population.

Does ZIP code 99328 have a large veteran population?

13% of civilians in ZIP code 99328 are veterans, above the national average of ~7%.

What is the population of ZIP code 99328?

ZIP code 99328 has an estimated population of 3,669 residents, with a density of 6 people per square mile.

What timezone is ZIP code 99328 in?

ZIP code 99328 observes the PST timezone.