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Last Updated on October 28, 2026 by Muhammad Toqeer
Every round-up for these leads with the decibel rating. The two manufacturers here publish 85 dB and 86 dB, both measured at ten feet.
One decibel. That is at or below what a person can reliably tell apart, and it is the number the listings put in bold.
The specification that actually decides this purchase is the enclosure — and one of these two manufacturers states it not as a rating but as a prohibition.
Why is the decibel rating the wrong place to start?
Because one decibel is not a difference you can act on.
Both figures are published honestly and both are measured the same way — at ten feet. SJE-Rhombus states 85 dB for the Tank Alert XT. Liberty states 86 dB for the ALM-Series. Neither is louder than the other in any way that matters in a basement.
So if loudness does not separate them, something else has to. It does, and it is not subtle.
Where will the alarm box actually live?
Answer this before you look at anything else, because it eliminates one of these two brands outright.
SJE’s Tank Alert XT is built to sit outside. The catalogue specification reads: “indoor/outdoor, weatherproof, thermoplastic, meets Type 3R water-tight standard”, with a “UL LIsted, Type 4X beacon assembly” and a test/silence switch “certified to IP66 and IP68 standards”.
Liberty’s ALM-Series is not, and the manual does not leave it as a judgement call. The feature list says “NEMA 1 enclosure – Rated for indoor use only”, and the safety section states it twice:
“NEVER install this alarm system outdoors. The system is rated for indoor use only.”
That is a prohibition, not a preference. If your basin sits in an unheated garage, a crawlspace, or outdoors at a lift station, this is the whole decision and the rest of the page is detail.
If you are not sure what counts as outdoors for your installation, the basin sizing and siting article covers where these pits actually end up.
Does the part number match your basin?
This is the mistake that costs people a return, and the model number is the only thing that reveals it.
On Liberty, the suffix says which basin the alarm is for. From the manual’s own list:
“Snap-on enclosed float – (ALM-P1, ALM-P1-EYE, SJ10A, SJ10A-EYE) – Sump Pump Applications” “Tethered float – ( ALM-2, ALM-2-1, ALM-2-EYE, ALM-2-1-EYE) – Sewage Pump Applications”
The alarm box is identical. The sensor is not. A `-P1` ships a snap-on float that clips onto a sump pump’s discharge pipe. A `-2` ships the tethered float meant for a sewage basin. Order “a Liberty alarm” for a sewage pit and take delivery of a P1 and you have the right brand and the wrong product.
On SJE, the letters after the model number are a configuration code, printed in the catalogue:
“H = High Level L = Low Level X = No Float TB = Includes Terminal Block PC = Power Cord AUX = Auxiliary Contacts”
So a TAXT-01H arrives with a float, a TAXT-01X arrives without one, and TAXT-01HAUX adds auxiliary contacts for driving something else.
How deep is your basin?
Only one of these two manufacturers tells you.
**SJE publishes a maximum water depth for its float: “30 feet (9 meters), 13 psi”.** That is a real limit — a float sitting under a column of water has pressure on it, and the maker has stated how much it will take.
Liberty’s manual states no depth figure at all. That is not a fault, but it means that on an unusually deep basin you can check one of these against your installation and not the other.
SJE also rates its float for “sewage and non-potable water up to 140°F (60°C)”, which matters more than it sounds if a dishwasher or a washing machine discharges into the pit.
The five, and what each one publishes
Two manufacturers, five configurations. Nothing below is taken from a reseller listing.
SJE-Rhombus Tank Alert XT, TAXT-01H — the one that can go outside
120 VAC, 50/60 Hz. Enclosure 6.5 x 4.5 x 3 inches, “indoor/outdoor, weatherproof, thermoplastic, meets Type 3R water-tight standard”. Horn 85 dB at 10 feet, itself meeting the Type 3R standard as factory-installed. Type 4X beacon, UL Listed. Test/silence switch certified to IP66 and IP68. Ships standard with a 15 foot SJE SignalMaster control switch with mounting clamp; cable is 15 ft, 18 gauge, 2 conductor SJOW. Float 2.74 x 4.83 inches, polypropylene, rated for sewage and non-potable water to 140°F, maximum water depth 30 feet / 13 psi. Float switch electrical rating 5 amps, 125/250 VAC.
Who it is for: anyone whose alarm box cannot be guaranteed a dry indoor wall. It is the only option here that the manufacturer permits outdoors.
The honest drawback: no battery backup is listed in this specification. A weatherproof box on mains power still goes quiet in an outage, which is the exact moment a sewage basin fills — and that failure has its own article.
SJE-Rhombus TAXT-01HAUX — the same alarm that can trigger something else
The TAXT-01H with auxiliary alarm contacts, rated 120 VAC, 5 amps maximum, 50/60 Hz.
Who it is for: an installation where the alarm needs to drive a second device — a remote beacon, a building system, an autodialer — rather than just sound where it stands.
The honest drawback: 5 amps is the ceiling, so the contacts switch a signal or a small load, not a pump. And it is a different part number, so it has to be specified at order rather than added later.
SJE-Rhombus TAXT-01X — the alarm without a float
The same weatherproof alarm supplied with no float switch.
Who it is for: a basin that already has a serviceable float, or a control panel arrangement where the level signal comes from elsewhere. It is also how you buy this alarm with a float other than the standard SignalMaster.
The honest drawback: it is only a saving if your existing float is actually sound. Reusing a float that has been sitting in a sewage basin for years to save a modest amount on a new alarm is a false economy.
Liberty ALM-2 — the indoor one with the right sensor
NEMA 1 enclosure, indoor only. 86 dB at 10 feet siren with a 360° red beacon. 9 V battery back-up with a low-battery indicator, which chirps “about twice per minute” when it needs replacing. Tethered float, the sewage-basin sensor. Level sensor arrives with a pre-installed connector for “plug-and-play installation”. Auxiliary dry contacts for triggering an external alarm. Automatic alarm and alarm-silence reset. 4 ft power cord. Three-year limited warranty.
Who it is for: a basin in a finished or at least enclosed basement, where the box goes on an indoor wall. The battery backup is the thing SJE’s specification does not list, and in an outage it is the whole point of an alarm.
The honest drawback: the enclosure is a hard limit, stated as a prohibition. And the 4 ft cord decides where it can hang more than people expect.
Liberty ALM-2-EYE — the same alarm that reaches your phone
The ALM-2 with NightEye wireless. The manual describes “Internet connectivity available with NightEye™ enabled devices”. Same NEMA 1 indoor-only enclosure, same 86 dB siren, same 9 V backup, same tethered sewage float, same three-year warranty.
Who it is for: a basin at a property you are not always in — a rental, a second home, a basement nobody visits. A siren nobody is there to hear is not a warning.
The honest drawback: it is still indoor-only, and it depends on your network. Wi-Fi in a basement near a sewage basin is exactly where coverage tends to be worst, and a power cut takes the router down with everything else even though the alarm’s own battery keeps it sounding.
Side by side
| Model | Enclosure | Horn | Battery backup | Sensor | Depth rating | Warranty |
|---|---|---|---|---|---|---|
| TAXT-01H | Type 3R, indoor/outdoor | 85 dB @ 10 ft | not listed | SignalMaster float | 30 ft / 13 psi | — |
| TAXT-01HAUX | Type 3R, indoor/outdoor | 85 dB @ 10 ft | not listed | SignalMaster float | 30 ft / 13 psi | — |
| TAXT-01X | Type 3R, indoor/outdoor | 85 dB @ 10 ft | not listed | none supplied | — | — |
| ALM-2 | NEMA 1, indoor only | 86 dB @ 10 ft | 9 V | Tethered, sewage | not stated | 3 yr |
| ALM-2-EYE | NEMA 1, indoor only | 86 dB @ 10 ft | 9 V | Tethered, sewage | not stated | 3 yr |
A dash means the manufacturer does not publish that figure in the document this page was built from. Note that the two columns that actually separate these brands — enclosure and battery backup — point in opposite directions. One brand can go outside but does not list a battery; the other has the battery and may not go outside.
Which one should you buy?
One question first, and it is not about the alarm.
Where will the box hang? If there is any chance it is outdoors, an unheated garage, or an open crawlspace, it is the Tank Alert XT and the decision is made. Liberty’s manual forbids the alternative.
If it is indoors, the battery decides it. An alarm without backup power is silent in an outage, and an outage is when a sewage pump stops and the basin starts filling. That makes the ALM-2 the stronger indoor choice, and the ALM-2-EYE if nobody is reliably in the building to hear it.
Then match the part number to the basin. `-2` for sewage, not `-P1`. On SJE, `H` if you need the float, `X` if you already have one.
And if your alarm is already fitted and sounding, this is the wrong page — start with why it is going off.
When does this need a pro?
The wiring, if the alarm is not a plug-in. SJE’s power cord is an optional item on the Tank Alert XT; without it this is a hard-wired device on a 120 VAC circuit.
The auxiliary contacts, if you are using them. Driving another device from an alarm is a circuit in its own right, and 5 amps is the stated ceiling.
Anything involving entering the basin. A sewage pit is a confined space, and that is not a DIY risk worth taking to position a float.
What you can do yourself: decide where the box will hang and whether that location is indoors by the manufacturer’s definition, measure the depth from the float’s working level to the top of the basin, and confirm which sensor your pump arrangement needs. Three answers, and they narrow this page to one row — or send you back to the pillar to reconsider the whole arrangement.
FAQ
How loud should a sewage pump alarm be?
Loud enough to hear from where people actually are, which is a question about the building rather than the product. The two manufacturers here publish 85 dB and 86 dB at ten feet — a one-decibel difference that should not drive the decision. Placement and whether the alarm has battery backup matter far more.
Can a sewage pump alarm be installed outdoors?
Only if the manufacturer rates it for that. SJE’s Tank Alert XT is specified as indoor/outdoor, weatherproof, meeting the Type 3R water-tight standard, with a Type 4X beacon. Liberty’s ALM-Series is a NEMA 1 enclosure and its manual states plainly never to install it outdoors.
Does a sewage pump alarm need a battery?
It needs one to be useful in a power cut, which is a common reason the pump stopped in the first place. Liberty’s ALM-Series includes a 9 V backup with a low-battery indicator that chirps about twice a minute. The Tank Alert XT specification does not list a battery backup.
What is the difference between ALM-P1 and ALM-2?
The sensor, not the alarm. The manual assigns the snap-on enclosed float to sump pump applications and the tethered float to sewage pump applications, with P1 models carrying the former and 2 models the latter. For a sewage basin you want the tethered float.
What do the letters in a Tank Alert part number mean?
The catalogue decodes them: H is high level, L is low level, X is no float, TB includes a terminal block, PC adds a power cord and AUX adds auxiliary contacts. So TAXT-01H ships with a float and TAXT-01X does not.
How deep can the float go?
SJE publishes a maximum water depth of 30 feet, or 13 psi, for its float, and rates it for sewage and non-potable water up to 140°F. Liberty’s manual states no depth figure, so on a deep basin only one of these can be checked against your installation.
How often should a sewage pump alarm be tested?
Liberty recommends testing every six months, and replacing the 9 V battery whenever the low-battery indicator is lit or every twelve months regardless. An alarm that has never been tested is an assumption rather than a warning.
