The means test
National Treasury's own words confirm the Older Person's Grant is reduced on a sliding scale based on income — but the Regulations that carry the actual thresholds and taper rate are not sourced here. This page explains exactly what is and is not known.

A confirmed mechanism, an unconfirmed rate
National Treasury’s own Budget Review states, in its own words, that grant values follow “the sliding scale, which bases grant values on recipients’ incomes”. That confirms a real income test exists and that it is a taper — a sliding scale — rather than a hard cut-off. What it does not do is state the scale itself: the income thresholds and the taper rate that would tell a reader how much a given income reduces the grant by.
The income test's thresholds and taper rate are not sourced here.
An income test exists — Treasury’s own Budget Review describes a sliding scale that reduces the grant based on a claimant’s income — but the thresholds and taper rate that set the scale sit in Regulations made under section 32 of the Social Assistance Act, published only by gazette, and no gazette-cited figure for them is available to this site.
The assets test's thresholds are not sourced here either.
An assets test is named alongside the income test, but no gazette-cited threshold for it is available to this site either.
Why the gap exists
The actual thresholds and taper rate live in the Regulations made under the Social Assistance Act, published by gazette — not in the Act’s own text and not in the Budget Review. None of gov.za, sassa.gov.za and saflii.org carries a readable copy of those Regulations. Several secondary sites do quote threshold figures, but they disagree with each other and none cites the gazette they claim to be quoting — publishing any one of them would be worse than publishing none, and this page does not.
What that means for a reader
This page cannot tell you the income or asset level at which the grant starts tapering, or the level at which it reaches zero. What it can tell you is the maximum the taper is applied to — see the grant amount — and that the reduction applies the same way whether or not you are married, since no couple-specific rate was found either. For the actual thresholds that apply to your own circumstances, contact SASSA directly.