Monthly billing, and seperate meter reading for the HWS ?
You have a normal usage and a controlled load then ?
Your other bill reading for home lighting etc is reasonable / not noticeably changed ?
A few things to consider.
Having an older analogue meter means you are on fixed 'single' tariff, possibly with off peak, possibly with CL (controlled load).
If you have a digital meter, you could be on fixed, or TOU (time of use), and some residential consumers in some states / regions are also being pushed onto demand tariff on top of that.
Is this a recent problem, or ongoing ?
"Each month that rolls around" indicates it's every month , and for some time.
Is the bill concerned an actual read, or an estimate ?
Often estimates are very high.
Has your plan or rates changed ?
A few states recently had significant increases.
Compare previous bills, both KWH used and cost.
If just the HWS metering reading that seemingly high, and your have a digital smart meter, you can download the data CSV from your usage page, and see when the HWS is coming on for the CL (controlled load), work out costs etc based on your rates.
If you have an old analogue meter, you might be getting just one actual reading every quarter, and the other 2 bills monthly billings as estimates, you can take a reading yourself from the CL meter and compare to bills, have adjusted if necessary (by phone or in the app before a bill period end or reading is due).
If you have an older analogue meter, you might have a boost switch, and somehow this might be accidentally turned to 'day' setting, where it will come on at normal peak rate.
You might have a malfunctioning HWS.
