But Zuma has said he does not know about the details, a claim that has been backed by Public Works Minister Thulas Nxesi.
"I don't know how much it costs," Zuma said in reply to a question put to him earlier this month, explaining that he did not ask about the details of security arrangements for Cabinet ministers either.
In Parliament this week, Nxesi said if anyone was to blame for overspending at the president's private home it would be his department, reinforcing an earlier statement that public works had simply implemented plans drawn up by state intelligence agencies, the police and defence force.
Under ethics rules, this would mean Zuma was in contravention of the Ministerial Handbook, with which Cabinet ministers, although not necessarily the president himself, must comply.
In terms of the handbook, an office bearer must submit a formal request for public works "to make a contribution towards security measures" recommended by police evaluators. The official is then not only responsible for getting quotations for the work, but must also claim the money spent from the department of public works before paying it to the contractors involved.
Nxesi originally claimed that the work done at the Nkandla compound had complied with the requirements of the handbook, which sets a reviewable maximum expenditure on security at private homes of R100 000, although he later said the work had been in compliance with the National Key Points Act.
But this law states clearly that security spending at a declared key point – ordered by the minister of defence in the interests of the country – is for the account of the owner.
This, in the case of the Nkandla home, is either the Ingonyama Trust, which owns the land on which it is built on behalf of Zulu King Goodwill Zwelithini, or Zuma, the lawful occupant. The trust is the landowner in law of 2.7-million hectares of KwaZulu-Natal.
Failure to spend the money necessary to secure a key point without reasonable cause can carry a jail term of up to five years under the Act.
The law empowers the minister of defence to "take, or cause to be taken, any or all of the steps which in his opinion are or may become necessary in respect of the security" of a key point – but only with the consent of the owner, who remains liable for the cost, unless the minister chooses to reduce the liability.
The payment for state spending on securing key points, should an owner fail to comply or the state offer a loan or contribution, should come from a specially created account – the special account for the safeguarding of national key points.
But documents released by the department of public works (which now denies releasing them) as well as leaked information reveal that about R240-million spent at the Zuma house was ascribed to the public works portfolio for accommodation for very, very important persons (VVIPs).
Parliament's standing committee on public accounts this week deferred a decision on whether to investigate the Nkandla spending. A similar preliminary inquiry by the public protector is under way.
Among the issues that might be investigated is the extent to which security costs were inflated with what a senior source close to the matter has described as "inflated concern" by those tasked with the security assessment, which required the construction of underground bunkers.
The bulletproof glass used at Nkandla, the source told the Mail & Guardian, had to be specially manufactured because it was required to be of a higher standard than that regularly used by banks, cash-in-transit companies and in other high-risk areas. "They are extremely paranoid, worse than security specialists in the United States," said the source, who wanted to remain anonymous.
Last week City Press published figures showing R3-million was spent on bulletproof glass at the homestead. The company identified as the supplier, South African Bullet Resistant Glass, would not comment on either the cost or the nature of the product it had supplied.