A depth-to-water reading you can trust, taken from the top of casing in seconds. Lower the probe until the alarm sounds, read the tape, done — accurate to about 1/100 of a foot per 100 feet. Tapes are laser-marked in engineering scale (hundredths of a foot) or in metric, and the probe carries stainless steel conductors on a polyethylene-coated steel tape that stays flexible in the cold and doesn't stretch under its own weight.

PFAS-free construction — important where sampling protocols prohibit fluoropolymer-containing equipment in the well.

ET or ETL?

Both are the same instrument and the same accuracy — the difference is reel size and depth range, and it's built into the length you pick below:

• ET — Electric Tape. 100, 200, and 300 ft (30, 60, 100 m). The compact, lighter reel for routine monitoring-well work.
• ETL — Electric Tape Long. 500, 750, and 1000 ft (150, 225, 300 m). A larger reel carrying the extra tape for deeper wells.

Choose your configuration — 3 steps

1. Tape material. Poly or MDPE — both polyethylene-coated steel. MDPE runs slightly less per length. ETFE-coated tape is available on request.
2. Probe diameter. 5/8" (1.59 cm) is the standard and is field serviceable — you can rebuild it yourself in the field. 3/8" (0.95 cm) fits tight annular spaces, narrow piezometers, and wells already occupied by a pump or transducer, but it is not field replaceable. Pick 3/8" only when clearance genuinely requires it.
3. Length and markings. ET covers 100–300 ft / 30–100 m; ETL covers 500–1000 ft / 150–300 m. The tape is marked in feet or metres, never both, so order the units your logs are recorded in.

Deeper than 1000 ft? See the ETL manual rewind reel (1500–3000 ft / 450–925 m) or the ETL electric rewind reel (up to 5000 ft) — past about 1000 ft, hand-winding a wet tape stops being practical.

Features

• Durable polypropylene storage reel on a solid aluminum frame
• Field-serviceable 5/8" probe with stainless steel conductors
• Adjustable sensitivity to prevent false triggering in humid or cascading wells
• Audible and visual alert on water contact
• Built-in reel hanger — hang it on the casing instead of setting it in the mud
• Leader Guard included, for longer tape life at the probe end
• Auto shut-off to protect the battery
• Easily replaced 9-volt battery
• Foam grip handle and tape protector

Parts & accessories

Accessories and every repair part are in Geotech WLM Parts & Accessories:

• Padded carrying bag — water-resistant, sized separately for ET and ETL reels. Not included.
• Tape weight, guide, and guard — sink the probe in deep or crooked wells, and protect the tape at the casing edge.
• Replacement tape — ET (100–300 ft) or ETL (500–1000 ft)
• Probe assembly, reel assembly, control assembly, and frame assembly
• Knobs, O-rings, and hardware, plus buzzers and battery holders

Documentation

• ET / ETL Water Level Meters — specifications (PDF)
• Water Level Meter — user manual (PDF)

Unsure which probe or length suits your wells? Contact us — we build these in Denver and can advise on the right configuration.