Lake levels › Hawaii

Koolau Reservoir water level today

Higher than usual for this time of year

1,038.30ft

feet above sea level ·

vs normal for Oct 10+0.4 ft
24 hours−0.01 ft
7 days+0.0 ft
30 days−1.2 ft
vs a year ago+0.4 ft

Is Koolau Reservoir low right now?

Koolau Reservoir was at 1,038.30 ft on October 10, 2026. That is 0.41 ft above the typical level for October 10 — higher than in 9 of 10 past years. Over the past week the lake has been steady.

Last 12 monthsDaily level Normal range (10–90% of past years)
1,0371,0391,0401,0421,043NovDecJanFebMarAprMayJunJulAugSepOct

Koolau Reservoir on Oct 10 in past years

20251,037.9+0.4
20241,037.9+0.4
20231,037.9+0.4

Level on the same date each year, and how today compares.

Daily levels, last two weeks

DateLevel (ft)Change
Oct 101,038.31±0.00
Oct 91,038.31+0.12
Oct 81,038.19+0.12
Oct 71,038.07−0.04
Oct 61,038.11−0.05
Oct 51,038.16−0.04
Oct 41,038.20−0.05
Oct 31,038.25−0.03
Oct 21,038.28−0.01
Oct 11,038.29+0.01
Sep 301,038.28−0.03
Sep 291,038.31−0.06
Sep 281,038.37−0.06
Sep 271,038.43+0.01

Daily means of the operator's readings (midnight to midnight, local time).

About Koolau Reservoir

10-year range
1,037.9 ft (July 10, 2026) to 1,042.8 ft (March 21, 2026)
Data
U.S. Geological Survey — USGS 16206600
Datum
LMSL (gage datum 1032 ft + gage height)

Lakes near Koolau Reservoir

Questions

Is Koolau Reservoir low right now?

Koolau Reservoir was at 1,038.30 ft on October 10, 2026. That is 0.41 ft above the typical level for October 10 — higher than in 9 of 10 past years. Over the past week the lake has been steady.

How often is the Koolau Reservoir level updated?

The operator reports every 15 minutes to an hour. This page refreshes several times a day; the time of the latest reading is shown next to the level.

Where does this data come from?

U.S. Geological Survey (USGS 16206600). Readings are provisional and can be revised.