SwimZone

Lake · Pickaway County · OH

Is Deer Creek Lake safe to swim?

Advisory

Blue-green algae is above the safe-contact threshold.

Updated July 22, 2026 · EPA CyAN satellite

Recent rain
1.3 in
Water type
Lake
Last updated
Jul 22
Bacteria
E. coli, fecal
Not monitored
Tested
Not monitored

No bacteria advisory or sampling for this water.

Blue-green algae
cyanobacteria
Advisory
Tested
662,435
cells/mL
Advisory over
100,000
cells/mL

Cyanobacteria 662,435 cells/mL (satellite, 7-day max), imaged 2026-07-21.

Sampled Jul 21 · EPA CyAN satellite

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There's an advisory on Deer Creek Lake right now.

Get an alert the day it clears, and every time a new one goes up.

What's in the water at Deer Creek Lake right now

As of July 22, 2026, Deer Creek Lake in Pickaway County, Ohio is not recommended for swimming. Satellite imagery measured 662,435 cells/mL of blue-green algae on July 21, 2026, above the 100,000 cells/mL advisory threshold. Rainfall over the past week totaled 1.3 in, which can wash bacteria and nutrients into the water.

How this read is built

Blue-green algae at Deer Creek Lake

Deer Creek Lake is a lake in Pickaway County, Ohio covering about 2 sq mi, the 19th-largest of the 41 lakes SwimZone monitors in Ohio. Satellite imagery measured 662,435 cells/mL of blue-green algae on July 21, 2026, above the 100,000 cells/mL advisory threshold.

Blue-green algae (cyanobacteria) blooms are most common from midsummer into early fall, when the water is warm, calm, and rich in nutrients from runoff. They can produce toxins that make people sick and can be rapidly fatal to dogs, so skip water that looks green, scummy, or like spilled paint, and keep children and pets out of it.

Bloom history at Deer Creek Lake

From EPA CyAN's satellite archive

2020: peak 1,236,468 cells/mL — above the 100,000 advisory level202021: peak 1,308,648 cells/mL — above the 100,000 advisory level212022: peak 985,424 cells/mL — above the 100,000 advisory level222023: peak 1,201,885 cells/mL — above the 100,000 advisory level232024: peak 1,424,895 cells/mL — above the 100,000 advisory level242025: peak 1,308,648 cells/mL — above the 100,000 advisory level252026: peak 471,306 cells/mL — above the 100,000 advisory level26Advisory100k cells/mL

Each bar is that summer's peak satellite reading (log scale). The red cap is the part above the advisory level.

Over 7 summers of satellite monitoring since 2020, Deer Creek Lake has reached blue-green algae advisory levels in 7 of them, most recently in July 2026. This is a lake that blooms most summers. Its highest recorded reading was 1,424,895 cells/mL in June 2024.

When to swim at Deer Creek Lake

It is currently peak season for blue-green algae, when warm, calm water lets blooms form fastest. This lake has bloomed in most monitored summers (7 of 7), historically peaking around June. Early summer, before the water fully warms, has generally been the safer window here; check the current read before you go either way.

Frequently asked: swimming in Deer Creek Lake

Is it safe to swim in Deer Creek Lake right now?
Deer Creek Lake is not recommended for swimming today. Satellite imagery measured 662,435 cells/mL of blue-green algae on July 21, 2026, above the 100,000 cells/mL advisory threshold. Conditions can change quickly with wind, heat, and rain, so check the posted signs and look at the water before you get in.
Does Deer Creek Lake have blue-green algae (cyanobacteria)?
Yes. Satellite monitoring measured 662,435 cells/mL of blue-green algae (cyanobacteria) at Deer Creek Lake on July 21, 2026, above the 100,000 cells/mL advisory level. Avoid swimming and keep children and pets out of the water.
Can dogs swim in Deer Creek Lake?
No. Blue-green algae at Deer Creek Lake is above the safe-contact threshold (662,435 cells/mL on July 21, 2026). Cyanobacteria toxins can be rapidly fatal to dogs, which swallow it while swimming and lick it from their fur. Keep dogs out of the water and away from any scum along the shore.
How often does Deer Creek Lake have blue-green algae blooms?
Over 7 summers of satellite monitoring since 2020, Deer Creek Lake has reached blue-green algae advisory levels in 7 of them, most recently in July 2026. This is a lake that blooms most summers. Its highest recorded reading was 1,424,895 cells/mL in June 2024.
How many Ohio lakes and beaches are unsafe for swimming today?
Today, 33 Ohio waters are above a safe-contact threshold and 32 more warrant caution, out of 101 monitored waters SwimZone tracks in the state.
How is Deer Creek Lake's water quality measured?
SwimZone builds this read from EPA CyAN satellite imagery for blue-green algae, official beach and fecal-bacteria advisories where a program monitors Deer Creek Lake, and a recent-rainfall overlay, all refreshed daily. It was last updated July 22, 2026.

Before you swim: the basics

Swim spots near Deer Creek Lake

All Ohio →

Of the 6 monitored waters nearest Deer Creek Lake, 4 are flagged today.

WaterDistanceTodayAlgae readSampled
Paint Creek LakeLake · Ross County26 miAdvisory445,311 cells/mLJul 21
Lake ChoctawLake · Madison County27 miAdvisory1,465,895 cells/mLJul 21
Rocky Fork LakeLake · Highland County33 miAdvisory307,966 cells/mLJul 21
Clarence J Brown ReservoirReservoir · Clark County36 miClear to swimNone detectedJul 21
Cowan LakeLake · Clinton County39 miClear to swimNone detectedJul 21
Hoover ReservoirReservoir · Delaware County42 miAdvisory471,306 cells/mLJul 21