IN THESE tough economic times, we reach a point where we have to say "enough."

Such is the case with two of the five East Bay school parcel taxes on the November ballot. As sympathetic as we are to the plight of public schools, as much as we understand their horrible bind created by the dysfunction in Sacramento, we have to draw the line.

That's why we strongly endorse the ballot measures for the John Swett and Fremont school districts, where the school tax burden is modest; cautiously back the proposal in Oakland; and recommend voters reject plans for the high-tax Berkeley and West Contra Costa districts. All of the districts would probably make good use of the money. Our decisions were based on the tax burden residents already face in this troubled economy.

These parcel taxes, for school operations, would increase residents' property tax bills or, in Berkeley's case, extend an existing tax. In each district, residents already pay extra property taxes to retire voter-approved school construction bonds. In three districts the proposed parcel tax would be on top of another parcel tax.

To help property owners understand their total supplemental taxes for schools (bonds and parcel taxes combined), we calculated examples for the owner of a small house (1,500 square foot, $300,000 assessed valuation) and a large one (2,500 square feet, $600,000 assessed valuation).

Measure J, John Swett Unified School District ($96 per residential parcel, 1.5 cents per square foot for industrial and commercial): Residents already face extra school taxes of $40 per $100,000 assessed valuation to retire bonds. Measure J would raise total property tax supplements for schools from $120 annually to $216 for a small house, and from $240 to $336 for a large house. Measure J would expire in 2015. Recommendation: Yes.

Measure M, West Contra Costa Unified School District (7.2 cents per square foot): Residents already pay two additional parcel taxes, one $72 per parcel, the other 7.2 cents per square foot. Residents also pay to retire bonds on one of the state's largest school construction programs. Measure M would raise total property tax supplements for schools in the near future from $900 annually to $1,008 for a small house, and from $1,692 to $1,872 for a large house. Measure M would expire in 2015. Last spring, when we endorsed the district's latest bond measure, we said that would be it. We're surprised that the school board is coming back now for an additional parcel tax. The district shouldn't be asking for both in one year. Recommendation: No.

Measure H, Berkeley Unified School District (6.31 cents per square foot for residential, 9.46 cents per square foot for commercial): This is a 10-year extension of a parcel tax due to expire in 2013. The district also has a second, much-larger parcel tax (26.07 cents per square foot for residential and 39.29 per square foot for commercial and industrial). If voters pass Measure I, also on the November ballot, property owners will be paying more to retire construction bonds, bringing the total of property tax supplements for schools to about $992 a year for a small house and $1,823 for a large house. Considering the economy and the large burden taxpayers face, it's premature to asks voters to extend a parcel tax that still has three years left. Recommendation: No.

Measure K, Fremont Unified School District ($53 per parcel): Residents already pay extra school taxes of $43 per $100,000 assessed valuation to retire bonds. The effect of Measure K would be to raise total property tax supplements for schools from $129 annually to $182 for a small house, and from $258 to $311 for a large house. Measure K would expire in 2016. Recommendation: Yes.

Measure L, Oakland Unified School District ($195 per parcel): Measure L would double the district's existing parcel tax. That's added to an extra tax bill of about $147 per $100,000 assessed valuation to retire bonds. The effect of Measure L would be to raise total property tax supplements for schools from $636 annually to $831 for a small house, and from $1,077 to $1,272 for a large house. Measure L would expire in 2021. Oakland school taxes are already high, but they are not in the same league as West Contra Costa and Berkeley. For that reason, and given the severe challenges the district faces, we support this measure, but with a warning: This should be it. Don't come back asking city residents to pay even more. Recommendation: Yes.