waterbycounty
Federal water data

County water report

Marlboro County Water Report

Drinking-water compliance, watershed health, monitoring records, and river conditions for Marlboro County, South Carolina.

Water grade

A

Water score

86.0

State rank

#16

of 46

Health violations

0

EPA SDWIS, 5-year lookback

Watershed impaired

50.0%

4 water bodies assessed

Monitoring sites

3

1,030 recent measurements

Live streamflow

28%

PEE DEE RIVER NR BENNETTSVILLE, SC

Water at a glance

Key Water Indicators for Marlboro County

EPA SDWIS

Safety Grade

A

Score: 86.0 / 100

EPA SDWIS

Active Violations

0

5-year health-based lookback

EPA ATTAINS

Watershed Health

50% impaired

4 bodies assessed

USGS NWIS

Streamflow Snapshot

28% of mean

PEE DEE RIVER NR BENNETTSVILLE, SC

EPA WQP

Monitoring Sites

3

1,030 recent readings

Source: EPA SDWIS · Safe Drinking Water Information System

Drinking Water Compliance

Compliance grade

A

Based on EPA SDWIS compliance history.

Water score

Higher scores indicate cleaner recent compliance records.

86.0/100

Health violations

0

Health-based violations

Violations per 100K served

0.0

Population-normalized SDWIS rate

Editorial analysis

Understanding Marlboro County’s Water

Drinking Water Quality Overview

EPA SDWIS

Marlboro County earns an A grade for drinking water quality, scoring 86.0 out of 100. EPA's Safe Drinking Water Information System (SDWIS) records zero health-based violations over the past five years — a strong compliance signal for a largely rural county.

Watershed Conditions

EPA ATTAINS

Under the Clean Water Act §303(d), EPA ATTAINS tracks whether waterways meet quality standards for drinking, recreation, and aquatic life (reporting cycle: 2022). A substantial 50.0% of assessed waterways are impaired (2 of 4 water bodies) across Marlboro County's watersheds. The leading impairment cause is escherichia coli (e. coli). Impairment does not mean tap water is unsafe — it measures ambient waterway conditions upstream of treatment, not finished drinking water.

River & Streamflow Status

USGS NWIS

USGS NWIS gauge data (as of 2026-05-14T14:15:00.000-04:00) puts PEE DEE RIVER at 2.2k cfs — well below its long-term average at 28% of mean — low-flow conditions worth noting for water-dependent ecosystems. Streamflow is a leading indicator of drought stress, sediment load, and dilution capacity: low flows concentrate pollutants and warm water temperatures, stressing aquatic life and, in surface-water-dependent systems, the source water quality for treatment plants.

Monitoring Network

EPA WQP

EPA's Water Quality Portal (WQP) aggregates monitoring data from federal, state, and tribal agencies. Marlboro County has limited coverage with 3 active monitoring sites with 1,030 recent measurements on record. Predominant monitoring categories include physical and nutrient. More monitoring sites generally indicate greater scientific attention to local water conditions — and provide the baseline data that regulators use to set future impairment listings.

Editorial advisory

What the data suggests for Marlboro County

Water Verdict

Marlboro County receives an excellent water quality assessment with a grade of A and a score of 86.0 out of 100. The water supply meets or exceeds federal safety standards, and residents can generally drink tap water with confidence.

Violation Context

Marlboro County has recorded zero health-based violations, indicating no recent health-based violations in the reporting period. The violation rate is zero per 100,000 people served, which is the best possible outcome.

Consumer Guidance

The EPA compliance record for Marlboro County shows no recent health-based violations. Marlboro County's drinking-water compliance score is 86.0 out of 100. Watershed monitoring does show E. coli in local surface water — a reminder that treated drinking water and source-water quality are measured separately. Reviewing your utility's annual Consumer Confidence Report each July confirms that treatment is keeping pace with any upstream pressures. There are 3 active water-quality monitoring sites in Marlboro County. A pipeline streamflow snapshot from the PEE DEE RIVER gauge is also available on this page.

Regional Context

Marlboro County has better water quality than the average county in South Carolina. Its water score is 21.1 points higher than the state average, indicating stronger water system performance relative to neighboring counties.

Advisory text summarizes county-level public records and is not a replacement for your utility's current Consumer Confidence Report or direct local notices.

Contaminants & Resources

Key issues flagged in Marlboro County's water environment

Watershed Impairment Causes (EPA ATTAINS)

  • 1

    E. coli (bacteria)

    Impairment cause per EPA Clean Water Act §303(d) assessment

Source: EPA ATTAINS · Reporting cycle 2022

Official EPA Resources for Marlboro County

EPA How's My Waterway

Interactive watershed health data for Marlboro County

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for Marlboro County

Consumer Confidence Reports (SC)

Annual water quality reports from utilities in South Carolina

Clean Water Act §303(d)

Watershed Health

Impaired Water Bodies

50.0%

2 of 4 assessed

Moderate concern

Top Impairment Causes

  • 1

    ESCHERICHIA COLI (E. COLI)

Source: EPA ATTAINS · Reporting cycle 2022

Impairment is determined under the Clean Water Act §303(d): a water body is impaired when it fails to meet state-defined quality standards for designated uses (drinking, recreation, aquatic life). Assessment coverage varies by state; counties without assessed water bodies are not shown.

Past 5 years

Water Quality Monitoring

Monitoring Sites

3

Active in the past 5 years

Measurements Recorded

1.0K

1,030 total readings

Most Measured

  • Physical
  • Nutrient
  • Inorganics, Minor, Metals

Categories measured most frequently

Data from the EPA Water Quality Portal (WQP), aggregating monitoring records from federal, state, and tribal sources. Each measurement represents a single sample analyzed for a specific characteristic (e.g., E. coli, pH, dissolved oxygen, nitrogen).

Live USGS Streamgage

River & Stream Conditions

Current Discharge

2,200cfs

May 14, 6:15 PM UTC

vs Long-Term Average

28%

Well below typical

Primary Streamgage

PEE DEE RIVER NR BENNETTSVILLE, SC

USGS site
02130561
Drainage area
7,780 sq mi
Long-term mean
7,960 cfs

One representative streamgage (the one with the largest drainage area in the county). Many counties have multiple gauges; this view summarizes the primary one. The long-term mean is the full-record annual average; the percent-of-typical value compares the latest reading against that average.

Free tool

Estimate Your Water Costs

Water Cost Estimate

3

3 people  ·  ~225 gal/day

Annual Total

$558

Monthly

$47

Water Bill

$558/yr

Filter Cost

$0/yr

Safety Grade for Marlboro County:C — Moderate

Some violations or watershed impairment detected.

Estimates use the national average residential water rate ($0.0068/gal, EPA/AWWA 2023) and EPA WaterSense per-person consumption baseline (75 gal/person/day). Actual bills vary by utility, usage tier, and local infrastructure fees. For informational purposes only.

Try the full calculator →

Marlboro County has good water quality

Learn about water restrictions and conservation in your area.

Water Restrictions →

Frequently Asked Questions

What is the water quality in Marlboro County, South Carolina?
Marlboro County, South Carolina has a drinking-water quality grade of A with a score of 86.0/100, based on EPA SDWIS compliance data. The county has 0 health-based drinking water violations over the past 5 years. Watershed health, monitoring records, and streamflow snapshots are reported separately on this page.
Are there any water violations in Marlboro County?
Marlboro County has 0 health-based drinking water violations recorded by the EPA over the past 5 years. Health-based violations indicate instances where contaminant levels exceeded EPA Maximum Contaminant Levels (MCLs). Zero violations is an excellent record indicating consistent compliance with federal drinking water standards.
How healthy are the watersheds in Marlboro County?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 50.0% of Marlboro County's 4 assessed water bodies are classified as impaired (2 impaired). The top reported causes are ESCHERICHIA COLI (E. COLI). Impairment means the water body fails to meet state quality standards for at least one designated use — drinking water source, recreation, aquatic life, or fish consumption. Note: watershed impairment doesn't always translate to tap-water issues; treatment plants can remove most regulated contaminants.
How much water-quality monitoring happens in Marlboro County?
EPA's Water Quality Portal records 1,030 measurements from 3 monitoring sites in Marlboro County over the past five years. The most frequently measured characteristic groups are Physical, Nutrient, Inorganics, Minor, Metals. Each measurement is a single sample analyzed for one characteristic (E. coli, pH, dissolved oxygen, etc.). High monitoring density means more scientific evidence behind any reported signal — it does not by itself indicate water quality.
What's happening with rivers in Marlboro County right now?
Marlboro County's primary USGS streamgage on the PEE DEE RIVER has a pipeline snapshot of 2,200 cubic feet per second — 28% of the long-term mean of 7,959.94 cfs. This is well below typical — often a signal of drought stress on source water. For the latest gauge feed, visit waterdata.usgs.gov.
How does Marlboro County water compare to the South Carolina average?
Marlboro County's SDWIS water quality score of 86.0/100 is higher than the South Carolina state average of 64.9. The average water quality grade across South Carolina is C, based on data from 46 counties with available SDWIS data.
Is tap water safe to drink in Marlboro County?
Based on EPA SDWIS data, Marlboro County has a water quality grade of A (86.0/100). This indicates good to excellent water quality with strong SDWIS compliance. The grade speaks to the public water system, not the watershed — for watershed-level concerns, see the Watershed Health zone. For the most up-to-date information, contact your local water utility or review your Consumer Confidence Report (CCR).
Does Marlboro County have clean drinking water?
Marlboro County has 0 health-based drinking water violations according to EPA records. With a water quality score of 86.0/100 and grade A, the county's drinking water meets EPA standards with no recorded health violations. Note: drinking-water compliance speaks to the public water system, not necessarily to the watershed itself — check the Watershed Health zone for ATTAINS §303(d) data.
How does Marlboro County rank for water quality in South Carolina?
Marlboro County ranks #16 out of 46 counties in South Carolina by SDWIS water quality score (1 = best). With a score of 86.0/100, it falls in the top third of counties statewide. The ranking reflects EPA SDWIS compliance only — not watershed impairment, monitoring density, or streamflow, which are tracked separately on this page.

Counties with Similar Water Quality

Allendale County

South Carolina

A

86.0

Water score

Barnwell County

South Carolina

A

86.0

Water score

Calhoun County

South Carolina

A

86.0

Water score

Data Sources

Drinking-water compliance data from the EPA Safe Drinking Water Information System (SDWIS) via the ECHO enforcement database. Scores reflect compliance history and health-based violation counts.

Watershed health and impaired-waterway data from the EPA ATTAINS Clean Water Act §303(d) assessments, state-reported and EPA-finalized.

Water-quality monitoring counts from the EPA Water Quality Portal (WQP), federated USGS, EPA, and state agency sampling records over a rolling 5-year window.

Live streamflow from the USGS National Water Information System (NWIS), continuous discharge measurements from the largest-drainage gauge in each county, compared against the full-record long-term annual mean.

Disclaimer: This data is informational only. It is not health, legal, or professional advice. For concerns about your specific water supply, contact your local water utility.

By Evan Brooks, Data EditorUpdated Reviewed by Evan Brooks, Data Editor

Explore more data for Marlboro County

Property TaxCost of LivingCrime RateIncomeHealthSchoolsDisaster RiskWeatherCounty Score